Numerical dissipation effects on detached eddy simulation for compressor flows
Detached Eddy Simulation(DES)is a commonly used high-fidelity turbulence model for analyzing compressor flows.Achieving high-resolution turbulence simulations with DES requires limiting numerical dissipation.However,upwind schemes with significant dissipation remain prevalent in DES for compressor flows.This paper examines dissipation of various numerical schemes using a decaying isotropic turbulence test case.The study reveals that the 3rd-order upwind scheme exhibits excessive dissipation,particularly evident in the elimination of turbulent kinetic energy at high wavenumbers in the turbulent energy spectrum.While higher-order reconstruction schemes mitigate this issue,they still exhibit dissipative behavior at higher wavenumbers.To address this,an adaptive-dissipation scheme is introduced,incorporating a modified Riemann solver with an adaptive function.This scheme accurately predicts the turbulent energy spectrum across all wavenumbers.Compared with the outcomes of the adaptive-dissipation scheme and the 3rd-order upwind scheme in DES for a transonic centrifugal compressor,the former demonstrates superior performance.Furthermore,the adaptive-dissipation scheme excels in resolving small coherent structures within the compressor flow.In summary,this investigation emphasizes the importance of selecting numerical schemes with reduced dissipation for DES in compressor flows.Such an approach enhances the accuracy of compressor performance prediction and allows for higher-resolution depiction of flow structures.The presented adaptive-dissipation scheme emerges as a favorable choice for these purposes.
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