Pub Date : 2023-08-25DOI: 10.1177/09544100231197092
Jhan Jaider Bahamon Blanco
The shape of a nozzle wall influences the phenomena associated with the behaviour of the fluid movement within the flow field mathematically described by the Navier—Stokes equations. This article studies different drawing techniques for the aerodynamic tracing of the wall contour searched by Vitoshinsky, Bell, Metha and Sivells. To the system of equations of the design models are added the math formulas that define Sauer’s method for redesigning the length of the converging section modifying simultaneously the contour sketches. The aim is to obtain a better distribution of the physical properties and to avoid excessive pressure in a limited space that could affect the internal structure of the wall. Numerical methods are used to visualize the features of the wave propagation, boundary layer separation and flow separation pattern to survey the appearance of the stream generated within the geometric profile of the wall and the ejected flow. A computational analysis is developed to make a comprehensive assessment of different chosen wall contours, including an optimized wall shape using genetic algorithms through a process to find maximum and minimum values of the cross-sectional area to change the wall layout. The selection carries out based on design parameters with variable area contraction ratio (from low to high) in the convergent section for being simulated in a boundary condition with a low-pressure ratio (NPR). Experimental data from Hunter's research are used for validation of the results for a J2-type aerospace nozzle operating at an NPR of 3.413.
{"title":"Analysis of the convergent section of a C-D nozzle and its influence on airflow performance using evolutionary strategies","authors":"Jhan Jaider Bahamon Blanco","doi":"10.1177/09544100231197092","DOIUrl":"https://doi.org/10.1177/09544100231197092","url":null,"abstract":"The shape of a nozzle wall influences the phenomena associated with the behaviour of the fluid movement within the flow field mathematically described by the Navier—Stokes equations. This article studies different drawing techniques for the aerodynamic tracing of the wall contour searched by Vitoshinsky, Bell, Metha and Sivells. To the system of equations of the design models are added the math formulas that define Sauer’s method for redesigning the length of the converging section modifying simultaneously the contour sketches. The aim is to obtain a better distribution of the physical properties and to avoid excessive pressure in a limited space that could affect the internal structure of the wall. Numerical methods are used to visualize the features of the wave propagation, boundary layer separation and flow separation pattern to survey the appearance of the stream generated within the geometric profile of the wall and the ejected flow. A computational analysis is developed to make a comprehensive assessment of different chosen wall contours, including an optimized wall shape using genetic algorithms through a process to find maximum and minimum values of the cross-sectional area to change the wall layout. The selection carries out based on design parameters with variable area contraction ratio (from low to high) in the convergent section for being simulated in a boundary condition with a low-pressure ratio (NPR). Experimental data from Hunter's research are used for validation of the results for a J2-type aerospace nozzle operating at an NPR of 3.413.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77999712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-21DOI: 10.1177/09544100231195774
S. Afkhami, Nematollah Fouladi, Mahmoud PasandidehFard
One of the frequently reported defects of RANS-based turbulence models is overestimation of turbulent kinetic energy production in high speed separated flow problems, which causes significant prediction errors. The correct estimation of such flow in thrust optimized parabolic nozzles extremely depends upon the accurate prediction of the onset of flow separation. In this paper, firstly, the significant error of conventional RANS-based turbulence models is shown to predict the onset of flow separation in this type of nozzles. Then, the prediction accuracy is improved through the modification of the essential parameters of the generalized k-ω (GEKO) turbulence model. It was found that modifying the separation and mixing parameters of the GEKO model to realize the turbulent kinetic energy production resulted in the accurate prediction of onset of flow separation at the extensive range of nozzle pressure ratios. Using this modified model with new coefficients reduced the error of about 30% of the k-ω-sst model in estimating the onset of flow separation. Also, the nozzle pressure value at which the transition from free shock separation (FSS) to restricted shock separation (RSS) occurs is well predicted by this approach. After strengthening the turbulence model, the flow physics has been investigated with increasing and decreasing nozzle chamber pressure. The length of the separation shock and reflected shock waves which impose the presence of FSS or RSS patterns and transitional phenomena are discussed. Our new findings show that unlike the transition from FSS to RSS, the inverse transition from RSS to FSS did not depend on the length of the separation and reflective shocks.
{"title":"Evaluation of generalized k-ω turbulence model in strong separated flow estimation of thrust optimized parabolic nozzle","authors":"S. Afkhami, Nematollah Fouladi, Mahmoud PasandidehFard","doi":"10.1177/09544100231195774","DOIUrl":"https://doi.org/10.1177/09544100231195774","url":null,"abstract":"One of the frequently reported defects of RANS-based turbulence models is overestimation of turbulent kinetic energy production in high speed separated flow problems, which causes significant prediction errors. The correct estimation of such flow in thrust optimized parabolic nozzles extremely depends upon the accurate prediction of the onset of flow separation. In this paper, firstly, the significant error of conventional RANS-based turbulence models is shown to predict the onset of flow separation in this type of nozzles. Then, the prediction accuracy is improved through the modification of the essential parameters of the generalized k-ω (GEKO) turbulence model. It was found that modifying the separation and mixing parameters of the GEKO model to realize the turbulent kinetic energy production resulted in the accurate prediction of onset of flow separation at the extensive range of nozzle pressure ratios. Using this modified model with new coefficients reduced the error of about 30% of the k-ω-sst model in estimating the onset of flow separation. Also, the nozzle pressure value at which the transition from free shock separation (FSS) to restricted shock separation (RSS) occurs is well predicted by this approach. After strengthening the turbulence model, the flow physics has been investigated with increasing and decreasing nozzle chamber pressure. The length of the separation shock and reflected shock waves which impose the presence of FSS or RSS patterns and transitional phenomena are discussed. Our new findings show that unlike the transition from FSS to RSS, the inverse transition from RSS to FSS did not depend on the length of the separation and reflective shocks.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86781431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-21DOI: 10.1177/09544100231195190
Itimad D. J. Azzawi
A new subsonic blower wind tunnel design has been studied both numerically and experimentally; it is also referred to as “blower” wind tunnel. This paper is initially aimed to address each sequential stage of the wind tunnel design process. Rather than applying the standard method of modelling solely the flow in the test section, a large-scale CFD model of the whole wind tunnel was employed. The loss of every constituent element was calculated and then all the losses are added up to determine the power needed for the wind tunnel operation which is used as “intake fan” boundary conditions in the CFD model. Then, flow uniformity and turbulent intensity measurements in an empty test section using a pitot static tube and hot wire anemometer (HWA) were introduced to validate the CFD results. The results showed that flow quality was significantly affected by flow conditioners (uniformity devices) (honeycomb and mesh screens) in the settling chamber and wide-angle diffuser. Investigations were also conducted to evaluate the flow deficit in the wake area behind a convex hump model using both HWA and particle image velocimetry PIV. This was additional experimental tests carried out to validate the suitability of the wind tunnel designed for aerodynamic research.
{"title":"Design and characterizing of blower wind tunnel using experimental and numerical simulation","authors":"Itimad D. J. Azzawi","doi":"10.1177/09544100231195190","DOIUrl":"https://doi.org/10.1177/09544100231195190","url":null,"abstract":"A new subsonic blower wind tunnel design has been studied both numerically and experimentally; it is also referred to as “blower” wind tunnel. This paper is initially aimed to address each sequential stage of the wind tunnel design process. Rather than applying the standard method of modelling solely the flow in the test section, a large-scale CFD model of the whole wind tunnel was employed. The loss of every constituent element was calculated and then all the losses are added up to determine the power needed for the wind tunnel operation which is used as “intake fan” boundary conditions in the CFD model. Then, flow uniformity and turbulent intensity measurements in an empty test section using a pitot static tube and hot wire anemometer (HWA) were introduced to validate the CFD results. The results showed that flow quality was significantly affected by flow conditioners (uniformity devices) (honeycomb and mesh screens) in the settling chamber and wide-angle diffuser. Investigations were also conducted to evaluate the flow deficit in the wake area behind a convex hump model using both HWA and particle image velocimetry PIV. This was additional experimental tests carried out to validate the suitability of the wind tunnel designed for aerodynamic research.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85490358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-18DOI: 10.1177/09544100231190604
Siling Wang, Sichen Ji, Zhou Yang, Hongyan Sun
In this study, an attitude control scheme based on a three-track moving mass control mechanism is proposed to address the problems of the overcomplicated rotor components, low service life, and low reliability of coaxial dual-rotor unmanned air vehicles (UAV). The motion and aerodynamic models of a moving mass-actuated ducted coaxial dual-rotor UAV are derived. The rotational dynamic characteristics of a moving mass-actuated UAV (MAUAV) with different slider positions and mass ratios are analyzed. An attitude controller based on backstepping sliding mode control is designed to address the nonlinearity and uncertainty of the MAUAV rotation. Based on this, we developed a position controller using cascade sliding mode control. The simulation results demonstrate that the designed attitude controller can achieve a settling time of 1.438 s in the unit-step response and a steady-state error of less than 5% in the sinusoidal attitude-tracking experiment. Additionally, the designed position controller exhibited a better trajectory-tracking effect under different levels of gust disturbance than that of a linear quadratic regulator control-based position controller.
{"title":"The modeling and cascade sliding mode control of a moving mass-actuated coaxial dual-rotor UAV","authors":"Siling Wang, Sichen Ji, Zhou Yang, Hongyan Sun","doi":"10.1177/09544100231190604","DOIUrl":"https://doi.org/10.1177/09544100231190604","url":null,"abstract":"In this study, an attitude control scheme based on a three-track moving mass control mechanism is proposed to address the problems of the overcomplicated rotor components, low service life, and low reliability of coaxial dual-rotor unmanned air vehicles (UAV). The motion and aerodynamic models of a moving mass-actuated ducted coaxial dual-rotor UAV are derived. The rotational dynamic characteristics of a moving mass-actuated UAV (MAUAV) with different slider positions and mass ratios are analyzed. An attitude controller based on backstepping sliding mode control is designed to address the nonlinearity and uncertainty of the MAUAV rotation. Based on this, we developed a position controller using cascade sliding mode control. The simulation results demonstrate that the designed attitude controller can achieve a settling time of 1.438 s in the unit-step response and a steady-state error of less than 5% in the sinusoidal attitude-tracking experiment. Additionally, the designed position controller exhibited a better trajectory-tracking effect under different levels of gust disturbance than that of a linear quadratic regulator control-based position controller.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85706160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-18DOI: 10.1177/09544100231195377
Xianzong Meng, Kun Ye, Zhengyin Ye
Compared to the shock-free condition, the weak shock impingement stabilizes the flexible panel, while the strong shock impingement leads to the early onset of panel flutter with a significant increase in flutter amplitude and frequency. However, the reason for this change by shock impingement remains unclear. The current research examines the mechanism of this change by an in-house code where the von Kármán’s large deflection plate theory is coupled with two-dimensional Euler equations. Compared to the shock-free condition, the oblique shock impingement leads to the change of local dynamic pressure on the panel as well as the static pressure differential across the panel. The analysis on the influence of these changes indicates that, on the one hand, the average dynamic pressure on the panel becomes larger than the shock-free condition, accelerating the onset of panel flutter. On the other hand, the change of the static pressure differential across the panel alters the coupling characteristic between different natural frequencies (modes) of the panel structure. The dynamic response of panel flutter under shock impingements is dominated by the coupling between the second and third modes instead of the first two modes for panel flutter under the shock-free condition. The combined effect of these two changes leads to the change of flutter characteristics of the panel under shock impingement. These findings provide valuable insights into the mechanism of shock-induced panel flutter.
{"title":"Mechanism of characteristic change of panel flutter caused by oblique shock impingement","authors":"Xianzong Meng, Kun Ye, Zhengyin Ye","doi":"10.1177/09544100231195377","DOIUrl":"https://doi.org/10.1177/09544100231195377","url":null,"abstract":"Compared to the shock-free condition, the weak shock impingement stabilizes the flexible panel, while the strong shock impingement leads to the early onset of panel flutter with a significant increase in flutter amplitude and frequency. However, the reason for this change by shock impingement remains unclear. The current research examines the mechanism of this change by an in-house code where the von Kármán’s large deflection plate theory is coupled with two-dimensional Euler equations. Compared to the shock-free condition, the oblique shock impingement leads to the change of local dynamic pressure on the panel as well as the static pressure differential across the panel. The analysis on the influence of these changes indicates that, on the one hand, the average dynamic pressure on the panel becomes larger than the shock-free condition, accelerating the onset of panel flutter. On the other hand, the change of the static pressure differential across the panel alters the coupling characteristic between different natural frequencies (modes) of the panel structure. The dynamic response of panel flutter under shock impingements is dominated by the coupling between the second and third modes instead of the first two modes for panel flutter under the shock-free condition. The combined effect of these two changes leads to the change of flutter characteristics of the panel under shock impingement. These findings provide valuable insights into the mechanism of shock-induced panel flutter.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136062958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-18DOI: 10.1177/09544100231181872
Xiao Cao, Li Liu, Jiahao Ge, Dun Yang
This paper presents an overall scheme of a long-endurance small solar-powered convertible unmanned aerial vehicle (CUAV) that operates tilt-rotor for multiple hover tasks. First, a solar/battery hybrid energy strategy was proposed to comprehensively meet the requirements of CUAVs with long endurance and multiple hovers. The particular ability of the solar-powered fixed-wing unmanned aerial vehicle (UAV), pure battery-powered CUAV, and the proposed long-endurance solar-powered CUAV with multiple cruises and hovers were comparatively analyzed from an energy standpoint. Second, a suitable conceptual design method and process for small solar-powered CUAV was given, and the robustness of the designed CUAV was using three performance metrics under nominal conditions. The approach was then applied to design a 6.5 kg CUAV, which was initially tested in flight. Finally, the performance and application potential of the designed CUAV was evaluated with operating conditions, mission requirements, energy input, and perpetual flight capability.
{"title":"Conceptual design of long-endurance small solar-powered unmanned aerial vehicle with multiple tilts and hovers","authors":"Xiao Cao, Li Liu, Jiahao Ge, Dun Yang","doi":"10.1177/09544100231181872","DOIUrl":"https://doi.org/10.1177/09544100231181872","url":null,"abstract":"This paper presents an overall scheme of a long-endurance small solar-powered convertible unmanned aerial vehicle (CUAV) that operates tilt-rotor for multiple hover tasks. First, a solar/battery hybrid energy strategy was proposed to comprehensively meet the requirements of CUAVs with long endurance and multiple hovers. The particular ability of the solar-powered fixed-wing unmanned aerial vehicle (UAV), pure battery-powered CUAV, and the proposed long-endurance solar-powered CUAV with multiple cruises and hovers were comparatively analyzed from an energy standpoint. Second, a suitable conceptual design method and process for small solar-powered CUAV was given, and the robustness of the designed CUAV was using three performance metrics under nominal conditions. The approach was then applied to design a 6.5 kg CUAV, which was initially tested in flight. Finally, the performance and application potential of the designed CUAV was evaluated with operating conditions, mission requirements, energy input, and perpetual flight capability.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90659547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-18DOI: 10.1177/09544100231182268
H. Alimohammadi, R. Aghaei-Togh
The design of liquid-propellant engines (LPEs) has several challenges in setting the performance parameters. Accordingly, optimizing the design of a thrust chamber is of considerable importance that has been considered in several research projects. Previous research has focused on multidisciplinary design optimization (MDO). However, despite these efforts, the main issues remain. The present paper proposes a multi-objective multidisciplinary design optimization based on an efficient adaptive surrogate model of the thrust chamber to address these issues. The proposed method introduces a practical multidisciplinary optimization method based on an adaptive surrogate model that uses the moving least squares methodology, CCM, sensitivity analysis, and the elite multi-objective genetic algorithm (NSGAII). Due to the high importance of specific impulse and thrust-to-weight ratio, these two functions were used as target functions and in the NSGAII framework, the Pareto frontier was drawn for them. The proposed method is applied to a thrust-chamber engine test case. The results show that the target performance of the engine is improved, the specific impulse value is increased by 3.4 s, and the thrust-to-weight ratio is increased by 4%. These values represent significant advances in LPE engine design. The results obtained in this study indicate the potential of the proposed method in solving large-scale thrust-chamber design optimization problems.
{"title":"Multi-objective multidisciplinary design optimization of liquid-propellant engines thrust chamber based on a surrogate model","authors":"H. Alimohammadi, R. Aghaei-Togh","doi":"10.1177/09544100231182268","DOIUrl":"https://doi.org/10.1177/09544100231182268","url":null,"abstract":"The design of liquid-propellant engines (LPEs) has several challenges in setting the performance parameters. Accordingly, optimizing the design of a thrust chamber is of considerable importance that has been considered in several research projects. Previous research has focused on multidisciplinary design optimization (MDO). However, despite these efforts, the main issues remain. The present paper proposes a multi-objective multidisciplinary design optimization based on an efficient adaptive surrogate model of the thrust chamber to address these issues. The proposed method introduces a practical multidisciplinary optimization method based on an adaptive surrogate model that uses the moving least squares methodology, CCM, sensitivity analysis, and the elite multi-objective genetic algorithm (NSGAII). Due to the high importance of specific impulse and thrust-to-weight ratio, these two functions were used as target functions and in the NSGAII framework, the Pareto frontier was drawn for them. The proposed method is applied to a thrust-chamber engine test case. The results show that the target performance of the engine is improved, the specific impulse value is increased by 3.4 s, and the thrust-to-weight ratio is increased by 4%. These values represent significant advances in LPE engine design. The results obtained in this study indicate the potential of the proposed method in solving large-scale thrust-chamber design optimization problems.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87252883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The three-dimensional flows in an inward-turning inlet were numerically investigated at different incoming flow conditions. When the incoming flow conditions change, the shock angle and the shock interaction form of the external compression wave change, and the development of the near-wall low-energy fluid and the streamwise vortex is also affected. The impingement of the shock wave leads to a sharp increase in the vorticity of the low kinetic energy fluid. Under the pressure gradient caused by the shock wave, the high-vorticity fluid migrates from the cowl to the ramp and entrains the mainstream fluid to form a streamwise vortex, for which the velocity gradient ( ∂v/ ∂y + ∂w/ ∂z) along the vortex axis can accurately determine the rotation direction and the Hopf bifurcation position. By considering high Reynolds number flows, the pressure gradient along the vortex axis is developed to estimate the simplified dilation term (velocity gradient) due to its ease of measurement. However, the pressure gradient ( ∂p/ ∂x) along the vortex axis can lead to bias when evaluating the cross-flow state of the streamwise vortex, with the shock wave structure and high-vorticity fluid leading to under- and overestimation, respectively. This study provides a theoretical basis for an accurate determination of the flow state of a streamwise vortex in an inward-turning inlet and thus lays the foundation for effective vortex control.
{"title":"Development and evolution mechanism of streamwise vortex in an inward-turning inlet","authors":"Ziao Wang, Xu Xin, Ruoyu Chen, R. Huang, Chen Kong, Jun-tao Chang","doi":"10.1177/09544100231194882","DOIUrl":"https://doi.org/10.1177/09544100231194882","url":null,"abstract":"The three-dimensional flows in an inward-turning inlet were numerically investigated at different incoming flow conditions. When the incoming flow conditions change, the shock angle and the shock interaction form of the external compression wave change, and the development of the near-wall low-energy fluid and the streamwise vortex is also affected. The impingement of the shock wave leads to a sharp increase in the vorticity of the low kinetic energy fluid. Under the pressure gradient caused by the shock wave, the high-vorticity fluid migrates from the cowl to the ramp and entrains the mainstream fluid to form a streamwise vortex, for which the velocity gradient ( ∂v/ ∂y + ∂w/ ∂z) along the vortex axis can accurately determine the rotation direction and the Hopf bifurcation position. By considering high Reynolds number flows, the pressure gradient along the vortex axis is developed to estimate the simplified dilation term (velocity gradient) due to its ease of measurement. However, the pressure gradient ( ∂p/ ∂x) along the vortex axis can lead to bias when evaluating the cross-flow state of the streamwise vortex, with the shock wave structure and high-vorticity fluid leading to under- and overestimation, respectively. This study provides a theoretical basis for an accurate determination of the flow state of a streamwise vortex in an inward-turning inlet and thus lays the foundation for effective vortex control.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74260524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-14DOI: 10.1177/09544100231181869
M. B. Artuc, I. Bayezit
The combination of nonlinear indirect and direct adaptive control with an active fault-tolerant framework is proposed in this paper for quadrotor position tracking control under uncertain and fault conditions. An inner loop direct model reference adaptive controller generates the required force while moving along the reference trajectory, while nonlinear indirect adaptive controller maintains the required attitude angles. Furthermore, for uncertain conditions, our proposed framework provides significantly stable characteristics. Otherwise, when a fault occurs at actuators or sensors, the quadrotor vehicle cannot guarantee global asymptotic stability. This study contributes to an active fault-tolerant control strategy for solving the complex position tracking problem using the adaptive two-stage Kalman filter (ATSKF). Based on the fault information, a fault compensation term is added to the control law to improve convergence and system robustness in the presence of uncertain and fault conditions. Finally, simulation results show satisfactory performance for quadrotor vehicle position tracking, even with actuator faults and uncertainties.
{"title":"Robust adaptive quadrotor position tracking control for uncertain and fault conditions","authors":"M. B. Artuc, I. Bayezit","doi":"10.1177/09544100231181869","DOIUrl":"https://doi.org/10.1177/09544100231181869","url":null,"abstract":"The combination of nonlinear indirect and direct adaptive control with an active fault-tolerant framework is proposed in this paper for quadrotor position tracking control under uncertain and fault conditions. An inner loop direct model reference adaptive controller generates the required force while moving along the reference trajectory, while nonlinear indirect adaptive controller maintains the required attitude angles. Furthermore, for uncertain conditions, our proposed framework provides significantly stable characteristics. Otherwise, when a fault occurs at actuators or sensors, the quadrotor vehicle cannot guarantee global asymptotic stability. This study contributes to an active fault-tolerant control strategy for solving the complex position tracking problem using the adaptive two-stage Kalman filter (ATSKF). Based on the fault information, a fault compensation term is added to the control law to improve convergence and system robustness in the presence of uncertain and fault conditions. Finally, simulation results show satisfactory performance for quadrotor vehicle position tracking, even with actuator faults and uncertainties.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91160146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-07DOI: 10.1177/09544100231189803
Yusong Wang, Ke Xiong, Chunling Zhu, Chengxiang Zhu, Rongyin Guo, Lei Chen
Aircraft icing seriously jeopardizes flight safety. The design of aircraft anti-icing/de-icing systems requires a thorough understanding of the adhesion between the ice and the substrate. In this research, an experimental device that can be housed within a wing is designed and constructed. Simulation analysis of the interfacial stresses is performed, which reveals that increasing the load and the interface size led to a deterioration in the uniformity of stresses at the interface. In addition, the ice layer does not undergo cohesive damage during the tests. The normal ice adhesion strength is evaluated in an icing wind tunnel using the methodology outlined in this paper. Glaze ice exhibits an increase in normal adhesion strength at lower temperatures, whereas the trend is reversed for rime ice. The minimum adhesion strength occurs near the medium volume diameter (MVD) of 30 µm. Furthermore, the normal strength is significantly enhanced by increase in wind speed and surface roughness, as well as by surface painting. The adhesion strength of aluminum substrates to ice is greater compared to titanium and stainless steel. Compared to shear adhesion strength, normal adhesion strength is less sensitive to various influencing factors. The proposed experimental framework provides precise measurement of normal adhesion strength of impact ice in the icing wind tunnel.
{"title":"Research on normal ice adhesion strength in icing wind tunnel","authors":"Yusong Wang, Ke Xiong, Chunling Zhu, Chengxiang Zhu, Rongyin Guo, Lei Chen","doi":"10.1177/09544100231189803","DOIUrl":"https://doi.org/10.1177/09544100231189803","url":null,"abstract":"Aircraft icing seriously jeopardizes flight safety. The design of aircraft anti-icing/de-icing systems requires a thorough understanding of the adhesion between the ice and the substrate. In this research, an experimental device that can be housed within a wing is designed and constructed. Simulation analysis of the interfacial stresses is performed, which reveals that increasing the load and the interface size led to a deterioration in the uniformity of stresses at the interface. In addition, the ice layer does not undergo cohesive damage during the tests. The normal ice adhesion strength is evaluated in an icing wind tunnel using the methodology outlined in this paper. Glaze ice exhibits an increase in normal adhesion strength at lower temperatures, whereas the trend is reversed for rime ice. The minimum adhesion strength occurs near the medium volume diameter (MVD) of 30 µm. Furthermore, the normal strength is significantly enhanced by increase in wind speed and surface roughness, as well as by surface painting. The adhesion strength of aluminum substrates to ice is greater compared to titanium and stainless steel. Compared to shear adhesion strength, normal adhesion strength is less sensitive to various influencing factors. The proposed experimental framework provides precise measurement of normal adhesion strength of impact ice in the icing wind tunnel.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135998217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：