Pub Date : 2023-12-01DOI: 10.47176/jafm.16.12.1694
S. K. Arabaci, M. Pakdemirli†
The innovative bus designs, inspired by the whales, have been developed. The designs are confined to the frontal area of the buses. The new designs are named as the Beluga buses. Several variants of the models all mimicking Beluga whales are proposed. Both numerical analysis and experimental have been conducted to determine the drag coefficients of various models. The ANSYS CFD program was used for numerical simulations. WT tests were conducted to experimentally determine the drag coefficients. Both methods indicate that the beluga-inspired buses offer significant reductions in drag, which can lead to lower fuel consumption. The new beluga design is expected to reduce fuel consumption by 12.64%. Comparing the experimental and numerical results, a 6.4% discrepancy in the drag coefficients is observed at low Reynolds numbers, which became negligible at higher Reynolds numbers. The new geometry is expected to offer an economical solution for reducing fuel consumption.
{"title":"Aerodynamic Improvements of Buses Inspired by Beluga Whales","authors":"S. K. Arabaci, M. Pakdemirli†","doi":"10.47176/jafm.16.12.1694","DOIUrl":"https://doi.org/10.47176/jafm.16.12.1694","url":null,"abstract":"The innovative bus designs, inspired by the whales, have been developed. The designs are confined to the frontal area of the buses. The new designs are named as the Beluga buses. Several variants of the models all mimicking Beluga whales are proposed. Both numerical analysis and experimental have been conducted to determine the drag coefficients of various models. The ANSYS CFD program was used for numerical simulations. WT tests were conducted to experimentally determine the drag coefficients. Both methods indicate that the beluga-inspired buses offer significant reductions in drag, which can lead to lower fuel consumption. The new beluga design is expected to reduce fuel consumption by 12.64%. Comparing the experimental and numerical results, a 6.4% discrepancy in the drag coefficients is observed at low Reynolds numbers, which became negligible at higher Reynolds numbers. The new geometry is expected to offer an economical solution for reducing fuel consumption.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":" 10","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138621295","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 : 2023-12-01Epub Date: 2023-02-09DOI: 10.1177/17585732231156403
Daniel Leslie James Morris, Jaime Candal-Couto, Adam Charles Watts, Amar Rangan, Amol Tambe
Aims: Long-term follow-up and monitoring of asymptomatic shoulder and elbow arthroplasty remains contentious, with a wide spectrum of non-evidence-based mechanisms used. This scoping review aims to outline related evidence, thereby informing research requirements.
Methods: Studies relevant to shoulder and elbow arthroplasty follow-up, surveillance and time-related failure were included. The review included randomised controlled trials, systematic reviews and economic studies indexed in MEDLINE, Embase, Cochrane CDSR and Cochrane CENTRAL since 1 January 2012. In addition, all registry studies, follow-up studies, cohort studies and case reports indexed in MEDLINE since 1 January 2020 were included. The screening was undertaken by two reviewers. Key characteristics of each study were described, alongside a narrative review.
Results: Twenty-one articles were included. We were unable to identify evidence that long-term follow-up and monitoring of asymptomatic shoulder and elbow arthroplasty identifies failure or leads to a revision that is of reduced patient morbidity and cost. In addition, no evidence was apparent to inform whether patients will self-present with a failing implant. Several surveillance mechanisms were identified.
Conclusion: This scoping review highlights the paucity of evidence related to long-term follow-up and monitoring of shoulder and elbow arthroplasty, and the need for high-quality data to inform the development of evidence-based care pathways.
{"title":"Scoping review: Evidence for long-term follow-up and monitoring in shoulder and elbow arthroplasty.","authors":"Daniel Leslie James Morris, Jaime Candal-Couto, Adam Charles Watts, Amar Rangan, Amol Tambe","doi":"10.1177/17585732231156403","DOIUrl":"10.1177/17585732231156403","url":null,"abstract":"<p><strong>Aims: </strong>Long-term follow-up and monitoring of asymptomatic shoulder and elbow arthroplasty remains contentious, with a wide spectrum of non-evidence-based mechanisms used. This scoping review aims to outline related evidence, thereby informing research requirements.</p><p><strong>Methods: </strong>Studies relevant to shoulder and elbow arthroplasty follow-up, surveillance and time-related failure were included. The review included randomised controlled trials, systematic reviews and economic studies indexed in MEDLINE, Embase, Cochrane CDSR and Cochrane CENTRAL since 1 January 2012. In addition, all registry studies, follow-up studies, cohort studies and case reports indexed in MEDLINE since 1 January 2020 were included. The screening was undertaken by two reviewers. Key characteristics of each study were described, alongside a narrative review.</p><p><strong>Results: </strong>Twenty-one articles were included. We were unable to identify evidence that long-term follow-up and monitoring of asymptomatic shoulder and elbow arthroplasty identifies failure or leads to a revision that is of reduced patient morbidity and cost. In addition, no evidence was apparent to inform whether patients will self-present with a failing implant. Several surveillance mechanisms were identified.</p><p><strong>Conclusion: </strong>This scoping review highlights the paucity of evidence related to long-term follow-up and monitoring of shoulder and elbow arthroplasty, and the need for high-quality data to inform the development of evidence-based care pathways.</p>","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":"9 1","pages":"593-601"},"PeriodicalIF":1.1,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10656974/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89786948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.47176/jafm.16.12.2092
S. Thanigaiarasu, G. Balamani, K. Mirnal, K. Revathy
The purpose of this study is to numerically analyze the effect of vortex generators that are shaped like vanes in enhancing the mixing of subsonic and sonic jet and to determine the best design which yields maximum reduction in jet potential core length and minimum thrust loss at the nozzle exit. Four different nozzle designs namely, models A, B, C and D are designed and compared with a base nozzle which is a plain circular nozzle without any vanes. The simulation is performed in ANSYS Fluent using the S-A turbulence model. The centerline pressure decay and radial pressure decay from models A to D are compared with that of the base nozzle to determine the ability of the vane to enhance the jet mixing characteristics. To evaluate the thrust loss, the total pressure at the exit plane of models A to D is measured and compared with that of the base nozzle. When comparing all the designs, it is observed that Model B produces the highest reduction in potential core length which is 66.4% at Mach no. 1 and Model D produces minimum total pressure loss which is 0.47% at Mach no. 0.4. In contrast to the conventional method, this design introduces a novel approach by placing the vanes parallel to the flow instead of the usual perpendicular arrangement. This unique configuration allows the vanes to redirect the flow rather than hinder it, resulting in a total pressure loss of less than 3%.
{"title":"Computational Study on the Effect of Vane Design in Enhancing the Mixing of Subsonic Jet and Sonic Jet","authors":"S. Thanigaiarasu, G. Balamani, K. Mirnal, K. Revathy","doi":"10.47176/jafm.16.12.2092","DOIUrl":"https://doi.org/10.47176/jafm.16.12.2092","url":null,"abstract":"The purpose of this study is to numerically analyze the effect of vortex generators that are shaped like vanes in enhancing the mixing of subsonic and sonic jet and to determine the best design which yields maximum reduction in jet potential core length and minimum thrust loss at the nozzle exit. Four different nozzle designs namely, models A, B, C and D are designed and compared with a base nozzle which is a plain circular nozzle without any vanes. The simulation is performed in ANSYS Fluent using the S-A turbulence model. The centerline pressure decay and radial pressure decay from models A to D are compared with that of the base nozzle to determine the ability of the vane to enhance the jet mixing characteristics. To evaluate the thrust loss, the total pressure at the exit plane of models A to D is measured and compared with that of the base nozzle. When comparing all the designs, it is observed that Model B produces the highest reduction in potential core length which is 66.4% at Mach no. 1 and Model D produces minimum total pressure loss which is 0.47% at Mach no. 0.4. In contrast to the conventional method, this design introduces a novel approach by placing the vanes parallel to the flow instead of the usual perpendicular arrangement. This unique configuration allows the vanes to redirect the flow rather than hinder it, resulting in a total pressure loss of less than 3%.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":" 62","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138614086","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 : 2023-12-01DOI: 10.47176/jafm.16.12.1983
†. J.Julian, W. I. F. Wahyuni
This study uses three turbulence model variations, i.e., S - A, k - ε, and k – ω turbulence models. In addition, there are two variations of cell shape and three variations of cell number. The number of cells is 500, 5000, 50000, and 100000. Verification is carried out in the mesh refinement study and validated by aerodynamic performances. Based on the mesh refinement study, quadrilateral cells with the k - ε are in the asymptotic convergence range. Based on the Cl, it can be concluded that the quadrilateral mesh with 50000 and 100000 cells simulated using the k-ε turbulence model shows very low errors, namely 4.1151% and 3.8643%, respectively. It shows consistency based on the quadrilaterals Cd mesh data with the k-ε and k-ω turbulence models. However, k-ε shows the lowest error with the number of cells 50000 and 100000, i.e., 127.7682% and 110.4175%, respectively. However, choosing mesh 50000 cells are advisable because it only takes 23 minutes 48 seconds in computation, while mesh 100000 cells take 1 hour 17 minutes 21 seconds. Only Cm from quadrilateral mesh with the turbulence model k-ω shows consistency. An error of mesh 50000 cells is 22.0717%, and the error value for 100000 cells is 18.1630%. By considering computation time, mesh 50000 cells are preferable because it only takes 27 minutes 16 seconds, which is faster 43 minutes 14 seconds than 100000 cells.
{"title":"Effect of Mesh Shape and Turbulence Model on Aerodynamic Performance at NACA 4415","authors":"†. J.Julian, W. I. F. Wahyuni","doi":"10.47176/jafm.16.12.1983","DOIUrl":"https://doi.org/10.47176/jafm.16.12.1983","url":null,"abstract":"This study uses three turbulence model variations, i.e., S - A, k - ε, and k – ω turbulence models. In addition, there are two variations of cell shape and three variations of cell number. The number of cells is 500, 5000, 50000, and 100000. Verification is carried out in the mesh refinement study and validated by aerodynamic performances. Based on the mesh refinement study, quadrilateral cells with the k - ε are in the asymptotic convergence range. Based on the Cl, it can be concluded that the quadrilateral mesh with 50000 and 100000 cells simulated using the k-ε turbulence model shows very low errors, namely 4.1151% and 3.8643%, respectively. It shows consistency based on the quadrilaterals Cd mesh data with the k-ε and k-ω turbulence models. However, k-ε shows the lowest error with the number of cells 50000 and 100000, i.e., 127.7682% and 110.4175%, respectively. However, choosing mesh 50000 cells are advisable because it only takes 23 minutes 48 seconds in computation, while mesh 100000 cells take 1 hour 17 minutes 21 seconds. Only Cm from quadrilateral mesh with the turbulence model k-ω shows consistency. An error of mesh 50000 cells is 22.0717%, and the error value for 100000 cells is 18.1630%. By considering computation time, mesh 50000 cells are preferable because it only takes 27 minutes 16 seconds, which is faster 43 minutes 14 seconds than 100000 cells.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":" 42","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138615900","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 : 2023-12-01DOI: 10.47176/jafm.16.12.1890
M. A. Fitriady, N. A. Rahmat, A. F. Mohammad
The aerodynamic interaction between the wake flow structure behind a single spire with a smooth wall boundary layer at a long streamwise location was observed in a wind tunnel experiment. The application of a single spire is intended to generate a wake flow similar to the one generated behind a skyscraper. A quarter elliptic wedge spire was used and a long streamwise distance of up to 26 times the spire’s height was adopted to ensure the development of the boundary layer and the wake recovery. To grasp how the smooth wall boundary layer interacts with the wake as well as how the wake recovers downstream, vertical and lateral velocity profiles were examined. Despite only one spire being utilized, it was found that the role of the spire as a vortex generator was confirmed the boundary layer height in the with-spire case increased compared to that of the without-spire case. Moreover, the velocity deficit recovery process was observed vertically and streamwise. However, within the boundary layer, the recovery rate in the streamwise direction was lower compared to the above it. This finding indicates that within the boundary, the turbulence generated can sustain the wake caused by the spire, reducing the recovery rate. Based on the current lateral velocity analysis, the final streamwise distance required by the wake to fully recover could not be predicted due to the large velocity deviation of 2.15% at the end of the streamwise distance.
{"title":"Vertical and Spanwise Wake Flow Structures of a Single Spire over Smooth Wall Surface in a Wind Tunnel","authors":"M. A. Fitriady, N. A. Rahmat, A. F. Mohammad","doi":"10.47176/jafm.16.12.1890","DOIUrl":"https://doi.org/10.47176/jafm.16.12.1890","url":null,"abstract":"The aerodynamic interaction between the wake flow structure behind a single spire with a smooth wall boundary layer at a long streamwise location was observed in a wind tunnel experiment. The application of a single spire is intended to generate a wake flow similar to the one generated behind a skyscraper. A quarter elliptic wedge spire was used and a long streamwise distance of up to 26 times the spire’s height was adopted to ensure the development of the boundary layer and the wake recovery. To grasp how the smooth wall boundary layer interacts with the wake as well as how the wake recovers downstream, vertical and lateral velocity profiles were examined. Despite only one spire being utilized, it was found that the role of the spire as a vortex generator was confirmed the boundary layer height in the with-spire case increased compared to that of the without-spire case. Moreover, the velocity deficit recovery process was observed vertically and streamwise. However, within the boundary layer, the recovery rate in the streamwise direction was lower compared to the above it. This finding indicates that within the boundary, the turbulence generated can sustain the wake caused by the spire, reducing the recovery rate. Based on the current lateral velocity analysis, the final streamwise distance required by the wake to fully recover could not be predicted due to the large velocity deviation of 2.15% at the end of the streamwise distance.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":" 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138614657","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 : 2023-12-01DOI: 10.47176/jafm.16.12.1949
P. Y. Zhou, Q. Ma, H. C. Xue, P. Y. Peng, C. H. Xie, L. Y. Xie, X. J. Zhang
The daily regulation and anti-regulation of upstream and downstream power stations, respectively, frequently alter the river flow regime, velocity, and surface gradient, thus resulting in unsteady flow characteristics of the river and hindering shipping, waterway maintenance, and wharf operations. This study investigated the influence of daily regulation on the navigation conditions in the deep reservoir by taking the rivers between the Three Gorges Dam and the Gezhouba Dam as the research object. Prototype observations and a depth-averaged 2-D model were used to determine the main factors affecting the propagation law of unsteady flow. The propagation pattern of unsteady flow and channel navigational conditions and measures of the power station were analyzed systematically. The results showed that the water level amplitude was affected primarily by the peak amplitude and duration of the peak shaving. Additionally, the base flow significantly influenced time spatial distributions of the water level amplitude. Impacted by the reservoir storage capacity, a threshold for the duration of peak shaving was noted; this may result in maximum water level variation. As the peak shaving duration increased, the amplitude of the water level decreased. The research results can provide theoretical support for the optimization of hub shipping.
{"title":"Effect of Daily Regulation on Navigation Conditions in Deep Reservoirs","authors":"P. Y. Zhou, Q. Ma, H. C. Xue, P. Y. Peng, C. H. Xie, L. Y. Xie, X. J. Zhang","doi":"10.47176/jafm.16.12.1949","DOIUrl":"https://doi.org/10.47176/jafm.16.12.1949","url":null,"abstract":"The daily regulation and anti-regulation of upstream and downstream power stations, respectively, frequently alter the river flow regime, velocity, and surface gradient, thus resulting in unsteady flow characteristics of the river and hindering shipping, waterway maintenance, and wharf operations. This study investigated the influence of daily regulation on the navigation conditions in the deep reservoir by taking the rivers between the Three Gorges Dam and the Gezhouba Dam as the research object. Prototype observations and a depth-averaged 2-D model were used to determine the main factors affecting the propagation law of unsteady flow. The propagation pattern of unsteady flow and channel navigational conditions and measures of the power station were analyzed systematically. The results showed that the water level amplitude was affected primarily by the peak amplitude and duration of the peak shaving. Additionally, the base flow significantly influenced time spatial distributions of the water level amplitude. Impacted by the reservoir storage capacity, a threshold for the duration of peak shaving was noted; this may result in maximum water level variation. As the peak shaving duration increased, the amplitude of the water level decreased. The research results can provide theoretical support for the optimization of hub shipping.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":"103 38","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138608026","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 : 2023-12-01DOI: 10.47176/jafm.16.12.1959
S. M. Belghoula, A. Benhamou
This study investigates numerical simulation for fluid-structure interaction in wind turbine blades, emphasizing the influence of dimensionless numbers. Utilizing OpenFoam, the Navier-Stokes equation is accurately solved with the PISO algorithm, ensuring proper interface conditions. The icoFsiFoam solver is validated through dynamic testing, demonstrating its effectiveness. In contrast to the widely adopted Blade Element Momentum Theory (BEMT), our approach focuses on analyzing blade deformation and resonance phenomena, capturing intricate deformations and stress concentrations. Our investigation explores the impact of reduced velocity on blade behavior across a range of 0.105 to 0.145, while consistently maintaining crucial dimensionless numbers such as Reynolds number (Re = 10⁶), Froude number (Fr = 4.93), and Cauchy number ( Cy = 10-5). The outcomes of this study significantly contribute to the understanding of fluid-structure interaction in wind turbine blades. By examining the oscillatory behavior of the blades, we observe trends similar to those predicted by BEMT. However, our approach surpasses BEMT by providing additional insights into stress concentrations and deformation modes. This advancement enables superior performance optimization and facilitates advanced blade analysis. The implications of our research are paramount for optimizing blade design and performance under varying reduced velocities. By incorporating the findings of this study, blade designers can make well-informed decisions to enhance the efficiency and durability of wind turbine technologies. The presented methodology and results provide a comprehensive investigation into the fluid-structure interaction of wind turbine blades, highlighting the importance of dimensionless numbers and their influence on blade behavior. Overall, this study offers valuable insights for improving wind turbine design and performance.
{"title":"Application of an Open-Source OpenFoam for Fluid-Structure Interaction Analysis of the Horizontal-Axis Wind Turbine Blade","authors":"S. M. Belghoula, A. Benhamou","doi":"10.47176/jafm.16.12.1959","DOIUrl":"https://doi.org/10.47176/jafm.16.12.1959","url":null,"abstract":"This study investigates numerical simulation for fluid-structure interaction in wind turbine blades, emphasizing the influence of dimensionless numbers. Utilizing OpenFoam, the Navier-Stokes equation is accurately solved with the PISO algorithm, ensuring proper interface conditions. The icoFsiFoam solver is validated through dynamic testing, demonstrating its effectiveness. In contrast to the widely adopted Blade Element Momentum Theory (BEMT), our approach focuses on analyzing blade deformation and resonance phenomena, capturing intricate deformations and stress concentrations. Our investigation explores the impact of reduced velocity on blade behavior across a range of 0.105 to 0.145, while consistently maintaining crucial dimensionless numbers such as Reynolds number (Re = 10⁶), Froude number (Fr = 4.93), and Cauchy number ( Cy = 10-5). The outcomes of this study significantly contribute to the understanding of fluid-structure interaction in wind turbine blades. By examining the oscillatory behavior of the blades, we observe trends similar to those predicted by BEMT. However, our approach surpasses BEMT by providing additional insights into stress concentrations and deformation modes. This advancement enables superior performance optimization and facilitates advanced blade analysis. The implications of our research are paramount for optimizing blade design and performance under varying reduced velocities. By incorporating the findings of this study, blade designers can make well-informed decisions to enhance the efficiency and durability of wind turbine technologies. The presented methodology and results provide a comprehensive investigation into the fluid-structure interaction of wind turbine blades, highlighting the importance of dimensionless numbers and their influence on blade behavior. Overall, this study offers valuable insights for improving wind turbine design and performance.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":" 5","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138614896","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 : 2023-12-01DOI: 10.47176/jafm.16.12.2030
D. A. Gubaidullin, †. B.A.Snigerev
Nonlinear acoustic oscillations of large amplitude created in a gas-filled tube under the action of two pistons located at the ends of the pipe are numerically investigated. The pistons oscillate according to the harmonic law at one of the natural frequencies and with different values of phase shift. The movement of the gas is described by mathematical equations of conservation for the main determining relations for the flow, which are estimated by applying the finite volume method based on OpenFOAM package. The non-stationary forced oscillatory motion of a gas inside an axisymmetric tube from a state of rest to a periodic steady motion is investigated. The features of nonlinear acoustic fluctuations of gas in cylindrical duct under the action of two pistons are found. The effect of the phase shift value has a strong effect on the oscillation amplitude of gas, when pistons oscillating at equal natural frequencies, in turn, when the pistons oscillate at different natural frequencies, the effect is very small. In particular, resonant oscillations are detected when the pistons vibrate at the same frequency values equal to odd values of their own higher harmonics in the absence of a phase shift value. In the case when the frequency values are equal to even values of the natural harmonics, resonant oscillations occur when the pistons move in anti-phase. The numerical method appears to work well and would be hoped for practical computations of different resonators.
{"title":"Numerical Study of Forced Nonlinear Acoustic Gas Oscillations in a Tube under the Action of Two Pistons with Phase Shift","authors":"D. A. Gubaidullin, †. B.A.Snigerev","doi":"10.47176/jafm.16.12.2030","DOIUrl":"https://doi.org/10.47176/jafm.16.12.2030","url":null,"abstract":"Nonlinear acoustic oscillations of large amplitude created in a gas-filled tube under the action of two pistons located at the ends of the pipe are numerically investigated. The pistons oscillate according to the harmonic law at one of the natural frequencies and with different values of phase shift. The movement of the gas is described by mathematical equations of conservation for the main determining relations for the flow, which are estimated by applying the finite volume method based on OpenFOAM package. The non-stationary forced oscillatory motion of a gas inside an axisymmetric tube from a state of rest to a periodic steady motion is investigated. The features of nonlinear acoustic fluctuations of gas in cylindrical duct under the action of two pistons are found. The effect of the phase shift value has a strong effect on the oscillation amplitude of gas, when pistons oscillating at equal natural frequencies, in turn, when the pistons oscillate at different natural frequencies, the effect is very small. In particular, resonant oscillations are detected when the pistons vibrate at the same frequency values equal to odd values of their own higher harmonics in the absence of a phase shift value. In the case when the frequency values are equal to even values of the natural harmonics, resonant oscillations occur when the pistons move in anti-phase. The numerical method appears to work well and would be hoped for practical computations of different resonators.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":"5 3","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138627469","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 : 2023-12-01DOI: 10.47176/jafm.16.12.1992
X. Tang, D. Chen, L. Liu, P. Zhu, L. Xin, M. Shi
The unsteady hypersonic flow under finite amplitude pulse entropy perturbation at different freestream temperatures was calculated by direct numerical simulation. The flow response characteristics under the perturbation of entropy waves in freestreaming are analyzed. The temperature effect of freestreaming is studied based on the sensitivity of the boundary layer caused by pulse entropy perturbation. The results show that the higher freestream temperature promotes the first growth of the above third-order modes after leaving the head region, and strongly inhibits the first attenuation. The influence of the freestream temperature on the evolution of the induced disturbance wave is more significant than that on the development of the main flow disturbance waves. Low freestream temperature can suppress the attenuation of the modes below the second order. As the disturbance wave evolves downstream, the frequency band of the finite frequency disturbance wave gradually narrows, and the frequency band narrows faster when the temperature of freestreaming is low than when the temperature of freestreaming is high.
{"title":"Freestream Temperature Effects on the Receptivity of Hypersonic Boundary Layer Induced by Finite-Amplitude Pulse Entropy Waves","authors":"X. Tang, D. Chen, L. Liu, P. Zhu, L. Xin, M. Shi","doi":"10.47176/jafm.16.12.1992","DOIUrl":"https://doi.org/10.47176/jafm.16.12.1992","url":null,"abstract":"The unsteady hypersonic flow under finite amplitude pulse entropy perturbation at different freestream temperatures was calculated by direct numerical simulation. The flow response characteristics under the perturbation of entropy waves in freestreaming are analyzed. The temperature effect of freestreaming is studied based on the sensitivity of the boundary layer caused by pulse entropy perturbation. The results show that the higher freestream temperature promotes the first growth of the above third-order modes after leaving the head region, and strongly inhibits the first attenuation. The influence of the freestream temperature on the evolution of the induced disturbance wave is more significant than that on the development of the main flow disturbance waves. Low freestream temperature can suppress the attenuation of the modes below the second order. As the disturbance wave evolves downstream, the frequency band of the finite frequency disturbance wave gradually narrows, and the frequency band narrows faster when the temperature of freestreaming is low than when the temperature of freestreaming is high.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":" 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138613191","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 : 2023-12-01DOI: 10.47176/jafm.16.12.1928
†. A.Dahia, A. L. D. Cheridi, M. Boumaza
Feedwater leakages due to excessive loads and cracking caused by corrosion or fatigue failure can affect the reliability of the production facilities. In the present work, a numerical study of a small leakage accident type SB-LOCA on the feed water pipeline was investigated using Computational Fluid Dynamics (CFD) and Relap5 computer codes. The aim is to understand the behavior of the incompressible water flow and its effect on the relevant parameters at the leakage location vicinity, including the mass flow rate, velocity, pressure, and temperature. For this, a mathematical model was developed and validated to evaluate the release of water through the pipe, which is mainly based on the variables that may affect the leakage. The results of CFD show that the leakage has important effects on the distribution of main parameters of the water flow through the pipe, which has an identical outcome from the Relap5 code simulation. The change of fluid velocity only has a little impact on the flow behavior at the leakage region.
{"title":"Transient Analysis of the Flow Behavior under a Small Leakage Accident in Feed Water Pipeline","authors":"†. A.Dahia, A. L. D. Cheridi, M. Boumaza","doi":"10.47176/jafm.16.12.1928","DOIUrl":"https://doi.org/10.47176/jafm.16.12.1928","url":null,"abstract":"Feedwater leakages due to excessive loads and cracking caused by corrosion or fatigue failure can affect the reliability of the production facilities. In the present work, a numerical study of a small leakage accident type SB-LOCA on the feed water pipeline was investigated using Computational Fluid Dynamics (CFD) and Relap5 computer codes. The aim is to understand the behavior of the incompressible water flow and its effect on the relevant parameters at the leakage location vicinity, including the mass flow rate, velocity, pressure, and temperature. For this, a mathematical model was developed and validated to evaluate the release of water through the pipe, which is mainly based on the variables that may affect the leakage. The results of CFD show that the leakage has important effects on the distribution of main parameters of the water flow through the pipe, which has an identical outcome from the Relap5 code simulation. The change of fluid velocity only has a little impact on the flow behavior at the leakage region.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":" 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138617755","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}
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