Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667236
M. Chao, Zhang Jun, Wu Mingnian, Miao Yaojun
Associating with a grooved cylinder, our research group designs a new type of low-wind-pressure conductor. Based on the OpenFOAM v5.0 platform, five different types of three-dimensional low-wind-pressure conductors and the standard conductor are numerically simulated by using the Large Eddy Simulation with Wall-adapting local eddy-viscosity (WALE) SGS model at Re=1.4×105. Firstly, the flow around a circular cylinder is calculated to prove the reliability of computation in this paper. The calculation results are then analyzed for the comparison of the drag coefficient, flow field characteristics and surface pressure coefficient of the low-wind-pressure conductors and the standard conductor, respectively. The drag coefficient agrees well with the experimental value. The reason for drag reduction in low-wind-pressure conductors is proved to be the generation of small-scale vortices in the surface grooves, which delay flow separation and reduce pressure drag. By comparing the average drag coefficient of the five types of low-wind-pressure conductors, the rougher surface gives rise to a worse drag reduction effect.
{"title":"Large Eddy Simulation of Flow over a New Type of Low-Wind-Pressure Conductor Using WALE Model","authors":"M. Chao, Zhang Jun, Wu Mingnian, Miao Yaojun","doi":"10.1109/IBCAST.2019.8667236","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667236","url":null,"abstract":"Associating with a grooved cylinder, our research group designs a new type of low-wind-pressure conductor. Based on the OpenFOAM v5.0 platform, five different types of three-dimensional low-wind-pressure conductors and the standard conductor are numerically simulated by using the Large Eddy Simulation with Wall-adapting local eddy-viscosity (WALE) SGS model at Re=1.4×105. Firstly, the flow around a circular cylinder is calculated to prove the reliability of computation in this paper. The calculation results are then analyzed for the comparison of the drag coefficient, flow field characteristics and surface pressure coefficient of the low-wind-pressure conductors and the standard conductor, respectively. The drag coefficient agrees well with the experimental value. The reason for drag reduction in low-wind-pressure conductors is proved to be the generation of small-scale vortices in the surface grooves, which delay flow separation and reduce pressure drag. By comparing the average drag coefficient of the five types of low-wind-pressure conductors, the rougher surface gives rise to a worse drag reduction effect.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128472136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667111
R. F. Latif, Syed Irtiza Ali Shah, Umar Rauf
Owing to the depletion of the fossil fuels and their ill-effects posed on the environment, the alternative renewable energy resources are receiving ever increasing focus of the modern world. Amid these resources, prospects of harvesting energy form the wind stand out because of its inexhaustible availability and cost-effectiveness. In spite of all the pros associated with the wind power, a con exists in the shape of low power density. Hence, to generate an amount of energy comparable with the other sources, numerous wind turbines are arrayed in a single wind farm. With this, arises the problem of wake interaction amongst the turbine arrays, owing to which, the downstream wind turbines exhibit a reduced output yield. This instigates a significant diminution in the efficiency of the succeeding wind turbines and, hence, their service life gets adversely affected as well. Much work has been inspired to attain a proper understanding of the wake interactions by developing wake interaction models. Notable amongst these models are the infinite wind farm boundary layer model, the Jensen model and its variant Jensen Park model, the Larsen model, FUGA and Ellipsys 3D model with RANS and LES variants. There exists enough data in the literature to prove that the Jensen’s wake model has long maintained its dominance over other models. This owes to its less computational cost yet with adequate accuracy in its predictions. In this work, an analysis of the velocity deficit aft of the wind turbine and its recovery along the downstream distance as calculated by the Jensen’s model has been compared with a case when a hybrid CFD-Jensen model technique is employed. As wind farm layout optimization is concerned with the optimal energy harvest through placement of maximum wind turbines within a limited area of the wind farm, the magnitude of output power losses along the downstream distance, becomes quite a significant concern. Hence, this analysis has been further extended to the estimation of output power losses as manifested by the succeeding wind turbines operating in the wakes, at different downstream distances. Furthermore, a comparative analysis of the angular spread of the wakes, as they travel downstream, is also presented. This study will be particularly useful for the cases when very little or no experimental data is available at hand, as it provides initial estimates for the wind farm layout optimization for optimal energy harvest.
{"title":"Analysis of Wind Turbine’s Velocity Deficit, Recovery and Output Power Losses using a Hybrid CFD-Jensen’s Wake Model Scheme","authors":"R. F. Latif, Syed Irtiza Ali Shah, Umar Rauf","doi":"10.1109/IBCAST.2019.8667111","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667111","url":null,"abstract":"Owing to the depletion of the fossil fuels and their ill-effects posed on the environment, the alternative renewable energy resources are receiving ever increasing focus of the modern world. Amid these resources, prospects of harvesting energy form the wind stand out because of its inexhaustible availability and cost-effectiveness. In spite of all the pros associated with the wind power, a con exists in the shape of low power density. Hence, to generate an amount of energy comparable with the other sources, numerous wind turbines are arrayed in a single wind farm. With this, arises the problem of wake interaction amongst the turbine arrays, owing to which, the downstream wind turbines exhibit a reduced output yield. This instigates a significant diminution in the efficiency of the succeeding wind turbines and, hence, their service life gets adversely affected as well. Much work has been inspired to attain a proper understanding of the wake interactions by developing wake interaction models. Notable amongst these models are the infinite wind farm boundary layer model, the Jensen model and its variant Jensen Park model, the Larsen model, FUGA and Ellipsys 3D model with RANS and LES variants. There exists enough data in the literature to prove that the Jensen’s wake model has long maintained its dominance over other models. This owes to its less computational cost yet with adequate accuracy in its predictions. In this work, an analysis of the velocity deficit aft of the wind turbine and its recovery along the downstream distance as calculated by the Jensen’s model has been compared with a case when a hybrid CFD-Jensen model technique is employed. As wind farm layout optimization is concerned with the optimal energy harvest through placement of maximum wind turbines within a limited area of the wind farm, the magnitude of output power losses along the downstream distance, becomes quite a significant concern. Hence, this analysis has been further extended to the estimation of output power losses as manifested by the succeeding wind turbines operating in the wakes, at different downstream distances. Furthermore, a comparative analysis of the angular spread of the wakes, as they travel downstream, is also presented. This study will be particularly useful for the cases when very little or no experimental data is available at hand, as it provides initial estimates for the wind farm layout optimization for optimal energy harvest.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126973274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667264
S. Shah
This paper discusses about the Pre-layout and Post-layout simulations methodology of DDR2 interface present between TMS3206455 (Microprocessor from Texas Instruments) and MT47H64M16 (DDR2 memory from Micron) of the controller card. Simulations have been performed in HyperLynx software. Simulation models used such as IBIS models, its validation and generated controller timing model for simulation is also discussed. Interface signals are simulated in LineSim which is Pre-layout simulation tool of HyperLynx software. Also described in this paper the constraints of signals which have been developed at the pre layout stage and ensures the proper timing of data, strobe, mask, address, control and command signals. The constraints are then exported to BoardSim which is used for Post-layout simulations. BoardSim Simulation results show the correlation with LineSim results and validate the timing between selected processor and DDR2 memory.
{"title":"Simulation Methodology of DDR2 Interface with TI Processor and Timing Verification in HyperLynx","authors":"S. Shah","doi":"10.1109/IBCAST.2019.8667264","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667264","url":null,"abstract":"This paper discusses about the Pre-layout and Post-layout simulations methodology of DDR2 interface present between TMS3206455 (Microprocessor from Texas Instruments) and MT47H64M16 (DDR2 memory from Micron) of the controller card. Simulations have been performed in HyperLynx software. Simulation models used such as IBIS models, its validation and generated controller timing model for simulation is also discussed. Interface signals are simulated in LineSim which is Pre-layout simulation tool of HyperLynx software. Also described in this paper the constraints of signals which have been developed at the pre layout stage and ensures the proper timing of data, strobe, mask, address, control and command signals. The constraints are then exported to BoardSim which is used for Post-layout simulations. BoardSim Simulation results show the correlation with LineSim results and validate the timing between selected processor and DDR2 memory.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125582264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667170
M. Shehzad, A. Bilal, Hasnain Ahmad
The Quadcopter Helicopters due to their unmatchable stability in Unmanned Aerial vehicle (UAV) class have gained control engineering community attraction during the last decade. It is an under actuated system with four inputs and six output states. Quadrotors are famous in route control and they can also be used as a testbed for testing, authentication and validation of control engineering laws in simulation and in a real-time environment. Testing, Authentication and Validation of a novel and proposed control algorithm is a pre requisite in Simulation on a plant with use of mathematical engineering tool i.e. LabVIEW or MATLAB. The Model of a plant can be chosen with reference to the proposed algorithm, so it can be linear or nonlinear. This proposed research work is a contribution in field of Intelligent flight controller Implementation and their comparison on Unmanned Aerial Vehicles (UAVs) family. This research work presents the implementation of Intelligent flight PID, LQR and State feedback controllers on nonlinear model of X3D Quadrotor. The implemented controllers have been tested, authenticated, validated and also compared in simulation using NI LabVIEW. The Control algorithms are implemented in a closed loop background to control the position & attitude of trajectory following Quadrotor Helicopter. To make the PID, LQR and state feedback control more challengeable, the model uncertainty and sensor noise has also been added to the plant. Although all the implemented controllers gives satisfactory feedback in stabilizing the quadrotor, but the comparison shows that the LQR controller because of its best performance, effectiveness and robustness in the plant, seems to be the best comparative implemented controller among them.
{"title":"Position & Attitude Control of an Aerial Robot (Quadrotor) With Intelligent PID and State feedback LQR Controller: A Comparative Approach","authors":"M. Shehzad, A. Bilal, Hasnain Ahmad","doi":"10.1109/IBCAST.2019.8667170","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667170","url":null,"abstract":"The Quadcopter Helicopters due to their unmatchable stability in Unmanned Aerial vehicle (UAV) class have gained control engineering community attraction during the last decade. It is an under actuated system with four inputs and six output states. Quadrotors are famous in route control and they can also be used as a testbed for testing, authentication and validation of control engineering laws in simulation and in a real-time environment. Testing, Authentication and Validation of a novel and proposed control algorithm is a pre requisite in Simulation on a plant with use of mathematical engineering tool i.e. LabVIEW or MATLAB. The Model of a plant can be chosen with reference to the proposed algorithm, so it can be linear or nonlinear. This proposed research work is a contribution in field of Intelligent flight controller Implementation and their comparison on Unmanned Aerial Vehicles (UAVs) family. This research work presents the implementation of Intelligent flight PID, LQR and State feedback controllers on nonlinear model of X3D Quadrotor. The implemented controllers have been tested, authenticated, validated and also compared in simulation using NI LabVIEW. The Control algorithms are implemented in a closed loop background to control the position & attitude of trajectory following Quadrotor Helicopter. To make the PID, LQR and state feedback control more challengeable, the model uncertainty and sensor noise has also been added to the plant. Although all the implemented controllers gives satisfactory feedback in stabilizing the quadrotor, but the comparison shows that the LQR controller because of its best performance, effectiveness and robustness in the plant, seems to be the best comparative implemented controller among them.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123088400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667108
M. Asif, Xiangzhou Guo, J. Miao, G. Mehdi
Passive imaging using Interferometric Aperture Synthesis requires intensive signal processing to form an image, with correlation as its core operation and the most compute intensive part. Correlators for power and space optimized applications, quite often, are designed with only a few levels of quantization e.g. 2-level, 3-level or 4-level. This article presents correlators with three different quantization schemes having same number of channels and sampling frequency. All three correlators are implemented for the same device to highlight the difference in hardware utilization, making it a reference for any relevant work. The 64-channel correlators are implemented for 2-level, 3-level and 4-level quantized input data. It requires to calculate 2016 real time correlations whereas the integration stage is capable of accumulating the correlation results for approximately 85 seconds with 800 MHz sampling frequency. The de-multiplexed architecture enables a collective throughput of 800M Correlations/second while running each parallel datapath at a clock frequency of 200 MHz. The design is implemented in Xilinx Vivado for Kintex family device whereas the design verification is accomplished by comparing register-transfer-level simulation results with ideal MATLAB results. The comparison made on the basis of device utilization shows that no big difference exists between 2-level, 3-level and 4-level correlators from hardware perspective.
{"title":"Coarsely Quantized Digital Correlators for Passive Millimeter Wave Imagers: A Hardware Perspective","authors":"M. Asif, Xiangzhou Guo, J. Miao, G. Mehdi","doi":"10.1109/IBCAST.2019.8667108","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667108","url":null,"abstract":"Passive imaging using Interferometric Aperture Synthesis requires intensive signal processing to form an image, with correlation as its core operation and the most compute intensive part. Correlators for power and space optimized applications, quite often, are designed with only a few levels of quantization e.g. 2-level, 3-level or 4-level. This article presents correlators with three different quantization schemes having same number of channels and sampling frequency. All three correlators are implemented for the same device to highlight the difference in hardware utilization, making it a reference for any relevant work. The 64-channel correlators are implemented for 2-level, 3-level and 4-level quantized input data. It requires to calculate 2016 real time correlations whereas the integration stage is capable of accumulating the correlation results for approximately 85 seconds with 800 MHz sampling frequency. The de-multiplexed architecture enables a collective throughput of 800M Correlations/second while running each parallel datapath at a clock frequency of 200 MHz. The design is implemented in Xilinx Vivado for Kintex family device whereas the design verification is accomplished by comparing register-transfer-level simulation results with ideal MATLAB results. The comparison made on the basis of device utilization shows that no big difference exists between 2-level, 3-level and 4-level correlators from hardware perspective.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129050410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667150
R. Yousaf, A. Javed, A. Shahzad
Increased demand for undetected surveillance along with data sensing and gathering capabilities has encouraged the researchers to explore new avenues in micro and nano air vehicle technology. Successful employment of fixed and rotary wing micro air vehicles in a vast array of roles have encouraged the scientists to develop bio-inspired flapping-wing micro air vehicles hence surpassing them in hovering and sharp turning at low-speed capabilities. These vehicles mimic birds such as hummingbird and many more. Their wings are constrained from the root; flexible nature of their material inhibits deformations and torsion during the flapping motion. Static deflections may lead to buckling or loss of lift due to higher torsion angles. Moreover, the cyclic motion of the wings may lead to material degradation resulting in an increased twist. This effects their aerodynamic performance and in the worst case may lead to fatigue failure. Therefore, it is of paramount importance to design the flexible wing with appropriate stiffness distribution for deformation, which may result in desirable aerodynamic and structural performance. Material selection for the flapping-wing unlike fixed wings is complex in nature due to the anisotropic property of reinforcement members and membranes used in the design. In this research, a comparison of different wing designs has been carried out using commercial finite element analysis software. In the first step, different wings of varying stiffness structure patterns of a Zimmerman planform (mimicking the humming-bird) have been designed. They consist of thin flexible carbon fiber and latex rubber membranes of varying strengths. Wing designs of different membrane materials and structural reinforcement patterns have been analyzed and compared in this work. Four such wings with an aspect ratio of 7.65 (wing length and root chord of 75 mm and 25 mm root, respectively) have been designed with different placement patterns of stiffness battens. This paper focuses on the stress, strain, deformation and modal analysis of the wings of various design configurations as a reaction to static forces applied at leading edge tip of the wing. After the analysis of the obtained results, the thickness of reinforced material has been decreased to three-fifth and one-fifth of the original thickness. The refinement in wing design has enabled the selection of the optimum design for given models and materials. The results show that Spread Batten Wing made of Capran membrane, with batten and membrane thickness of 0.2mm and 0.014mm is better amongst the designed wings to handle a load of 6g at higher operating frequencies (>100Hz). Whereas at lower operating frequencies (<50Hz), reinforcement of 0.6mm members along with 0.14mm thick Capran membrane is suitable for Leading edge reinforced wing and Leading & Trailing Edge reinforced wing. This study will augment in the appropriate selection of material and stiffness members in design finalization of the mi
{"title":"Static structural and modal analysis of Micro Air Vehicle flapping wing with varying stiffness structures","authors":"R. Yousaf, A. Javed, A. Shahzad","doi":"10.1109/IBCAST.2019.8667150","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667150","url":null,"abstract":"Increased demand for undetected surveillance along with data sensing and gathering capabilities has encouraged the researchers to explore new avenues in micro and nano air vehicle technology. Successful employment of fixed and rotary wing micro air vehicles in a vast array of roles have encouraged the scientists to develop bio-inspired flapping-wing micro air vehicles hence surpassing them in hovering and sharp turning at low-speed capabilities. These vehicles mimic birds such as hummingbird and many more. Their wings are constrained from the root; flexible nature of their material inhibits deformations and torsion during the flapping motion. Static deflections may lead to buckling or loss of lift due to higher torsion angles. Moreover, the cyclic motion of the wings may lead to material degradation resulting in an increased twist. This effects their aerodynamic performance and in the worst case may lead to fatigue failure. Therefore, it is of paramount importance to design the flexible wing with appropriate stiffness distribution for deformation, which may result in desirable aerodynamic and structural performance. Material selection for the flapping-wing unlike fixed wings is complex in nature due to the anisotropic property of reinforcement members and membranes used in the design. In this research, a comparison of different wing designs has been carried out using commercial finite element analysis software. In the first step, different wings of varying stiffness structure patterns of a Zimmerman planform (mimicking the humming-bird) have been designed. They consist of thin flexible carbon fiber and latex rubber membranes of varying strengths. Wing designs of different membrane materials and structural reinforcement patterns have been analyzed and compared in this work. Four such wings with an aspect ratio of 7.65 (wing length and root chord of 75 mm and 25 mm root, respectively) have been designed with different placement patterns of stiffness battens. This paper focuses on the stress, strain, deformation and modal analysis of the wings of various design configurations as a reaction to static forces applied at leading edge tip of the wing. After the analysis of the obtained results, the thickness of reinforced material has been decreased to three-fifth and one-fifth of the original thickness. The refinement in wing design has enabled the selection of the optimum design for given models and materials. The results show that Spread Batten Wing made of Capran membrane, with batten and membrane thickness of 0.2mm and 0.014mm is better amongst the designed wings to handle a load of 6g at higher operating frequencies (>100Hz). Whereas at lower operating frequencies (<50Hz), reinforcement of 0.6mm members along with 0.14mm thick Capran membrane is suitable for Leading edge reinforced wing and Leading & Trailing Edge reinforced wing. This study will augment in the appropriate selection of material and stiffness members in design finalization of the mi","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117081037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667163
Amjad Altaf, C. Xi, J. Miao
In last two decades, several microstrip BPF topologies have been investigated to meet more than 100% fractional bandwidth requirement of Ultra-Wideband (UWB) systems with pass-band from 3.1-10.6 GHz. This paper presents two compact C-band microstrip BPF structures inspired from design techniques of UWB BPF. These C-band BPF are designed for center frequency f0 of 6 GHz and fractional bandwidth around 67% covering complete C-band (4-8 GHz). The first proposed BPF is realized by using a combination of step impedance low pass filter (LPF) and the optimum distributed short-circuited stubs high pass filter (HPF). The second filter is designed using pseudo-interdigital stepped impedance resonators (PIDT-SIRS. Both filters have been implemented on commercial printed circuit board (PCB) of RO4350B substrate and each occupy an area less than 20 mil × 10 mil. These filters require minimum pass band variation so that they can be integrated with a gain equalizer circuit (4-8 GHz) without significant degradation of overall gain treatment by later circuit. Measured results observe close agreement to simulated results. Insertion loss of first BPF is 0.85dB ±0.2 dB and second BPF is 1 dB±0.3 dB.
{"title":"Design, Optimization and Realization of Two Compact C-band Microstrip BPF Structures","authors":"Amjad Altaf, C. Xi, J. Miao","doi":"10.1109/IBCAST.2019.8667163","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667163","url":null,"abstract":"In last two decades, several microstrip BPF topologies have been investigated to meet more than 100% fractional bandwidth requirement of Ultra-Wideband (UWB) systems with pass-band from 3.1-10.6 GHz. This paper presents two compact C-band microstrip BPF structures inspired from design techniques of UWB BPF. These C-band BPF are designed for center frequency f0 of 6 GHz and fractional bandwidth around 67% covering complete C-band (4-8 GHz). The first proposed BPF is realized by using a combination of step impedance low pass filter (LPF) and the optimum distributed short-circuited stubs high pass filter (HPF). The second filter is designed using pseudo-interdigital stepped impedance resonators (PIDT-SIRS. Both filters have been implemented on commercial printed circuit board (PCB) of RO4350B substrate and each occupy an area less than 20 mil × 10 mil. These filters require minimum pass band variation so that they can be integrated with a gain equalizer circuit (4-8 GHz) without significant degradation of overall gain treatment by later circuit. Measured results observe close agreement to simulated results. Insertion loss of first BPF is 0.85dB ±0.2 dB and second BPF is 1 dB±0.3 dB.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121391815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667187
M. Hussain, N. Khan
Aeroelastic tailoring is basically the use of directional stiffness to achieve desirable changes in our aerodynamic parameters. In this research paper, the aileron reversal speed of a fighter aircraft has been evaluated by modelling and subsequent analysis of the wing in FEMAP. The static aeroelastic analysis has been carried out at Mach 0.0 and sea level conditions and aileron deflection of 1 degree. The model was simulated at different dynamic pressures one by one and the speed of aileron control reversal was evaluated by examining the stability derivatives in the result file of FEMAP. The material properties of the wing were now changed and laminate element with 2D orthotropic material was used and wing central region was now given this composite property. The whole process of finding the aileron control reversal speed was again carried out and the results were compared with the previous case. An increase in the reversal speed was observed. This comparison would allow us to better comprehend the use and significance of directional stiffness in influencing our aerodynamic parameters of an aircraft. In the end recommendations for future work are also presented.
{"title":"Effect of Directional Stiffness on Control Reversal Speed","authors":"M. Hussain, N. Khan","doi":"10.1109/IBCAST.2019.8667187","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667187","url":null,"abstract":"Aeroelastic tailoring is basically the use of directional stiffness to achieve desirable changes in our aerodynamic parameters. In this research paper, the aileron reversal speed of a fighter aircraft has been evaluated by modelling and subsequent analysis of the wing in FEMAP. The static aeroelastic analysis has been carried out at Mach 0.0 and sea level conditions and aileron deflection of 1 degree. The model was simulated at different dynamic pressures one by one and the speed of aileron control reversal was evaluated by examining the stability derivatives in the result file of FEMAP. The material properties of the wing were now changed and laminate element with 2D orthotropic material was used and wing central region was now given this composite property. The whole process of finding the aileron control reversal speed was again carried out and the results were compared with the previous case. An increase in the reversal speed was observed. This comparison would allow us to better comprehend the use and significance of directional stiffness in influencing our aerodynamic parameters of an aircraft. In the end recommendations for future work are also presented.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122304911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667224
S. Lei, H. Yong
The lean blowout (LBO) is a critical aspect of combustion performance for gas turbine combustors. During the past decades, three major prediction methodologies for the LBO limits, i.e. the semi-empirical model, the numerical prediction method and the hybrid prediction method are proposed. The semi-empirical models are derived mainly based on two kinds of physics-based models, i.e. the characteristic time (CT) model and the perfect stirred reactor (PSR) model. Among these semi-empirical models, Lefebvre’s LBO model that is based on the PSR model had been validated on 8 different aero gas turbine combustors with the prediction uncertainty ±30% and applied widely on the prediction of the LBO limits. Subsequently, a series of studies have been done to further develop Lefebvre’s LBO model. The numerical prediction methods are studied increasingly with the dramatically increase of the computing power. Based on the open literature, the best prediction uncertainty of the numerical prediction methods could be within 14% for a fixed combustor configuration with 3 kinds of fuels. More validations of different combustor configurations, atomization and dispersion models are required for the further application of numerical prediction methods. The hybrid prediction methods combine the semi-empirical models and the numerical methods simultaneously and could be divided into 2 types, i.e. the numerical and the semi-empirical based hybrid methods. The numerical based hybrid prediction method requires more validations and some general criteria for different configurations and operating conditions. The semi-empirical based hybrid prediction method could achieve maximum and average prediction uncertainties about ±15% and ±5%, respectively, for 10 combustor configurations. In summary, all the prediction methodologies should be further developed to achieve much more accurate prediction for the LBO limits as well as ensure the good generality.
{"title":"An Overview of Methodologies to Predict Lean Blowout Limits for Gas Turbine Combustors","authors":"S. Lei, H. Yong","doi":"10.1109/IBCAST.2019.8667224","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667224","url":null,"abstract":"The lean blowout (LBO) is a critical aspect of combustion performance for gas turbine combustors. During the past decades, three major prediction methodologies for the LBO limits, i.e. the semi-empirical model, the numerical prediction method and the hybrid prediction method are proposed. The semi-empirical models are derived mainly based on two kinds of physics-based models, i.e. the characteristic time (CT) model and the perfect stirred reactor (PSR) model. Among these semi-empirical models, Lefebvre’s LBO model that is based on the PSR model had been validated on 8 different aero gas turbine combustors with the prediction uncertainty ±30% and applied widely on the prediction of the LBO limits. Subsequently, a series of studies have been done to further develop Lefebvre’s LBO model. The numerical prediction methods are studied increasingly with the dramatically increase of the computing power. Based on the open literature, the best prediction uncertainty of the numerical prediction methods could be within 14% for a fixed combustor configuration with 3 kinds of fuels. More validations of different combustor configurations, atomization and dispersion models are required for the further application of numerical prediction methods. The hybrid prediction methods combine the semi-empirical models and the numerical methods simultaneously and could be divided into 2 types, i.e. the numerical and the semi-empirical based hybrid methods. The numerical based hybrid prediction method requires more validations and some general criteria for different configurations and operating conditions. The semi-empirical based hybrid prediction method could achieve maximum and average prediction uncertainties about ±15% and ±5%, respectively, for 10 combustor configurations. In summary, all the prediction methodologies should be further developed to achieve much more accurate prediction for the LBO limits as well as ensure the good generality.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127972479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667130
Z. Abbas, A. Javed
Alternate means of energy harvesting, such as application of bio-inspired systems is an active area of research and has evolved as a novel design model. Birds and insects inspired Flapping foils exhibit substantially improved aerodynamic performance as compared to static wings. Formation of Leading edge vortex (LEV) and low pressure within, play fundamental part in higher instantaneous lift generation. In this study, numerical simulation of a Fully Active flapping foil energy harvester subjected to sinusoidal pitching and heaving motion is conducted to examine aerodynamic performance and efficiency. Analysis was carried out on a corrugated (dimpled) airfoil, which assists in timely travelling and development of leading edge vortex resulting in improved energy extraction performance. The airfoil is externally excited to undergo sinusoidal pitching and heaving motion at low Reynolds number (Re=1100). The net energy extraction can be accomplished under the effect of time changing fluid forces. ANSYS Fluent ® is employed to analyze the separation bubble travelling based on wavelength and amplitude at prescribed sinusoidal pitching and heaving motion with particular frequency and phase difference. The results indicate that corrugations (dimples) on the airfoil helps in timely travelling and growth of leading edge vortex. Moreover, the sinusoidal pitching motion improves the creation of leading edge vortex accompanied by harmonization of vertical velocity and vertical force by elevation of vertical force peak value. Corrugated (dimpled) airfoil exhibits early separation of flow and stronger LEV formation.
{"title":"Performance Enhancement of Fully Active Corrugated Flapping Foil Flow Energy Harvester","authors":"Z. Abbas, A. Javed","doi":"10.1109/IBCAST.2019.8667130","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667130","url":null,"abstract":"Alternate means of energy harvesting, such as application of bio-inspired systems is an active area of research and has evolved as a novel design model. Birds and insects inspired Flapping foils exhibit substantially improved aerodynamic performance as compared to static wings. Formation of Leading edge vortex (LEV) and low pressure within, play fundamental part in higher instantaneous lift generation. In this study, numerical simulation of a Fully Active flapping foil energy harvester subjected to sinusoidal pitching and heaving motion is conducted to examine aerodynamic performance and efficiency. Analysis was carried out on a corrugated (dimpled) airfoil, which assists in timely travelling and development of leading edge vortex resulting in improved energy extraction performance. The airfoil is externally excited to undergo sinusoidal pitching and heaving motion at low Reynolds number (Re=1100). The net energy extraction can be accomplished under the effect of time changing fluid forces. ANSYS Fluent ® is employed to analyze the separation bubble travelling based on wavelength and amplitude at prescribed sinusoidal pitching and heaving motion with particular frequency and phase difference. The results indicate that corrugations (dimples) on the airfoil helps in timely travelling and growth of leading edge vortex. Moreover, the sinusoidal pitching motion improves the creation of leading edge vortex accompanied by harmonization of vertical velocity and vertical force by elevation of vertical force peak value. Corrugated (dimpled) airfoil exhibits early separation of flow and stronger LEV formation.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132270501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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