The accuracy of large eddy simulation(LES)is highly dependent on the performance of sub-grid scale(SGS)model.In the present paper,a dynamic cubic nonlinear sub-grid scale model(DCNM)proposed by Huang et al.is implemen...The accuracy of large eddy simulation(LES)is highly dependent on the performance of sub-grid scale(SGS)model.In the present paper,a dynamic cubic nonlinear sub-grid scale model(DCNM)proposed by Huang et al.is implemented for the simulation of unsteady cavitating flow around a 3-D Clark-Y hydrofoil in OpenFOAM.Its performance in predicting the evolution of cloud cavitation is discussed in detail.The simulation with a linear model,the dynamic Smagorinsky model(DSM),is also conducted as a comparison.The results with DCNM show a better agreement with the available experimental observation.The comparison between DCNM and DSM further suggests that the DCNM is able to predict the backscatter more precisely,which is an important feature in LES.The characteristics of DCNM is analyzed to account for its advantages in the prediction of unsteady cloud cavitation as well.The results reveal that it is the nonlinear terms of DCNM that makes DCNM capture sub-grid scale vortices better and more suitable for studying the transient behaviors of cloud cavitation than DSM.展开更多
The stall in a centrifugal pump impeller under a quarter-load condition is investigated by using a third-order SGS model named the DCNM, for a better understanding of the rotation effect on the stall phenomenon. The s...The stall in a centrifugal pump impeller under a quarter-load condition is investigated by using a third-order SGS model named the DCNM, for a better understanding of the rotation effect on the stall phenomenon. The study of the distributions of the Reynolds stresses, the production tei*m and the rotation term reveals that the production and the rotation jointly result in the non-uniform Reynolds stress distribution. Further study of the two components of the production and the rotation shows that they jointly transport a certain energy from the Reynolds component R、to Ruu.展开更多
基金Supported by the National Natural Science Foundation of China(Grant Nos.51822903,11772239).
文摘The accuracy of large eddy simulation(LES)is highly dependent on the performance of sub-grid scale(SGS)model.In the present paper,a dynamic cubic nonlinear sub-grid scale model(DCNM)proposed by Huang et al.is implemented for the simulation of unsteady cavitating flow around a 3-D Clark-Y hydrofoil in OpenFOAM.Its performance in predicting the evolution of cloud cavitation is discussed in detail.The simulation with a linear model,the dynamic Smagorinsky model(DSM),is also conducted as a comparison.The results with DCNM show a better agreement with the available experimental observation.The comparison between DCNM and DSM further suggests that the DCNM is able to predict the backscatter more precisely,which is an important feature in LES.The characteristics of DCNM is analyzed to account for its advantages in the prediction of unsteady cloud cavitation as well.The results reveal that it is the nonlinear terms of DCNM that makes DCNM capture sub-grid scale vortices better and more suitable for studying the transient behaviors of cloud cavitation than DSM.
基金Project supported by the Key program of the Ministry of Education (Grant No. 113010A)the National Natural Science Foundation of China (Grant No. 51209206).
文摘The stall in a centrifugal pump impeller under a quarter-load condition is investigated by using a third-order SGS model named the DCNM, for a better understanding of the rotation effect on the stall phenomenon. The study of the distributions of the Reynolds stresses, the production tei*m and the rotation term reveals that the production and the rotation jointly result in the non-uniform Reynolds stress distribution. Further study of the two components of the production and the rotation shows that they jointly transport a certain energy from the Reynolds component R、to Ruu.
