Flows experiencing laminarization and retransition are universal and crucial in many engineering applications.The objective of this study is to conduct an uncertainty quantification and sensitivity analysis of turbule...Flows experiencing laminarization and retransition are universal and crucial in many engineering applications.The objective of this study is to conduct an uncertainty quantification and sensitivity analysis of turbulence model closure coefficients in capturing laminarization and retransition for a rapidly contracting channel flow.Specifically,two commonly used turbulence models are considered:the Spalart-Allmaras(SA)one-equation model and the Menter Shear Stress Transport(SST)two-equation model.Thereby,a series of steady Reynolds Averaged Navier-Stokes(RANS)predictions of aero-engine intake acceleration scenarios are carried out with the purposely designed turbulence model closure coefficients.As a result,both SA and SST models fail to capture the retransition phenomenon though they achieve pretty good performance in laminarization.Using the non-intrusive polynomial chaos method,solution uncertainties in velocity,pressure,and surface friction are quantified and analyzed,which reveals that the SST model possesses much great uncertainty in the non-laminar regime,especially for the logarithmic law prediction.Besides,a sensitivity analysis is performed to identify the critical contributors to the solution uncertainty,and then the correlations between the closure coefficients and the deviations of the outputs of interest are obtained via the linear regression method.The results indicate that the diffusion-related constants are the dominant uncertainty contributors for both SA and SST models.Furthermore,the remarkably strong correlation between the critical closure coefficients and the outputs might be a good guide to recalibrate and even optimize the commonly used turbulence models.展开更多
基金co-supported by the Youth Program of the National Natural Science Foundation of China (No. 11902367)the Youth Program of Natural Science Foundation of Hunan Province, China (Nos. S2021JJQNJJ2519 and S2021JJQNJJ2716)the Science and Technology Research and Development plan of China National Railway Group, China (Nos. P2020J025 and P2021J036)
文摘Flows experiencing laminarization and retransition are universal and crucial in many engineering applications.The objective of this study is to conduct an uncertainty quantification and sensitivity analysis of turbulence model closure coefficients in capturing laminarization and retransition for a rapidly contracting channel flow.Specifically,two commonly used turbulence models are considered:the Spalart-Allmaras(SA)one-equation model and the Menter Shear Stress Transport(SST)two-equation model.Thereby,a series of steady Reynolds Averaged Navier-Stokes(RANS)predictions of aero-engine intake acceleration scenarios are carried out with the purposely designed turbulence model closure coefficients.As a result,both SA and SST models fail to capture the retransition phenomenon though they achieve pretty good performance in laminarization.Using the non-intrusive polynomial chaos method,solution uncertainties in velocity,pressure,and surface friction are quantified and analyzed,which reveals that the SST model possesses much great uncertainty in the non-laminar regime,especially for the logarithmic law prediction.Besides,a sensitivity analysis is performed to identify the critical contributors to the solution uncertainty,and then the correlations between the closure coefficients and the deviations of the outputs of interest are obtained via the linear regression method.The results indicate that the diffusion-related constants are the dominant uncertainty contributors for both SA and SST models.Furthermore,the remarkably strong correlation between the critical closure coefficients and the outputs might be a good guide to recalibrate and even optimize the commonly used turbulence models.
