Modification of Spalart–Allmaras model with consideration of turbulence energy backscatter using velocity helicity

The correlation between the velocity helicity and the energy backscatter is proved in a DNS case of 2563-grid homogeneous isotropic decaying turbulence. The helicity is then proposed to be employed to improve turbulence models and SGS models. Then Spalart–Allmaras turbulence model (SA) is modified with the helicity to take account of the energy backscatter, which is significant in the region of corner separation in compressors. By comparing the numerical results with experiments, it can be concluded that the modification for SA model with helicity can appropriately represent the energy backscatter, and greatly improves the predictive accuracy for simulating the corner separation flow in compressors.

► We study the relativity between the velocity helicity and the energy backscatter. ► Spalart–Allmaras turbulence model is modified with the velocity helicity. ► The modified model is employed to simulate corner separation in compressor cascade. ► The modification can greatly improve the accuracy for predicting corner separation. ► The helicity can represent the energy backscatter in turbulence and SGS models.