On Shock Propagation through Double-Bend Ducts by Entropy-Generation-Based Artificial Viscosity Method

Arnab Chaudhuri

doi:10.3390/e21090837

Abstract

Shock-wave propagation through obstacles or internal ducts involves complex shock dynamics, shock-wave shear layer interactions and shock-wave boundary layer interactions arising from the associated diffraction phenomenon. This work addresses the applicability and effectiveness of the high-order numerical scheme for such complex viscous compressible flows. An explicit Discontinuous Spectral Element Method (DSEM) equipped with entropy-generation-based artificial viscosity method was used to solve compressible Navier–Stokes system of equations for this purpose. The shock-dynamics and viscous interactions associated with a planar moving shock-wave through a double-bend duct were resolved by two-dimensional numerical simulations. The shock-wave diffraction patterns, the large-scale structures of the shock-wave-turbulence interactions, agree very well with previous experimental findings. For shock-wave Mach number and reference Reynolds number , the predicted pressure signal at the exit section of the duct is in accordance with the literature. The attenuation in terms of overpressure for is found to be ≈0.51. Furthermore, the effect of reference Reynolds number is studied to address the importance of viscous interactions. The shock-shear layer and shock-boundary layer dynamics strongly depend on the while the principal shock-wave patterns are generally independent of .

Highlights

Shock/blast wave propagation involves complex wave interactions with the media and surface boundaries owing to several phenomena such as shock reflection, shock focusing, shock diffraction and shock-turbulence interaction
The shock-shear layer and shock-boundary layer dynamics strongly depend on the Ref while the principal shock-wave patterns are generally independent of Ref
The moving shock-wave after the passage through the inlet section gets diffracted over the top left corner of the domain

Summary

Introduction

Shock/blast wave propagation involves complex wave interactions with the media and surface boundaries owing to several phenomena such as shock reflection, shock focusing, shock diffraction and shock-turbulence interaction Understanding of these phenomena is crucial for a wide range of engineering applications in bio-medicine, disaster management, detonation, mining, aviation/transport industry and others. Knowledge of such complex dynamics is integral part of the design and optimization of devices for shock-wave lithotripsy, shock/blast-wave attenuation, suppression of tunnel sonic boom, etc. Numerical prediction is a cost effective option compared to its experimental counterpart accounting for several restrictions Resolving these unsteady dynamics by numerical techniques demands development of high-fidelity numerical tools. The inspiration behind this work is related to the applicability and effectivity of the high-order numerical tools resolving flow dynamics associated with shock-wave propagation and attenuation

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Results

Conclusion