Research Note

Sharif

, 28:3

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

ارزیابی مدل‌های تلاطمی در شبیه‌سازی اموج تیز‌ایستا در جریان‌های فوق بحرانی کانال‌ها‌

  • E. AlamatianAffiliated withDept. of Civil Engineering, Ferdowsi University Email author 
  • , M. R. JaefarzadehAffiliated withDept. of Civil Engineering, Ferdowsi University

EVALUATION OF TURBULENCE MODELS IN SIMULATION OF OBLIQUE STANDING SHOCK WAVES IN SUPERCRITICAL CHANNEL FLOWS

Abstract

In this article, the two-dimensional depth-averaged Saint Venant equations, including the turbulence terms, are solved in a supercritical flow with oblique standing waves, and the effects of several turbulence models on the performance of standing oblique shock waves are investigated. The algorithm applies the finite volume Roe- TVD method with unstructured triangular cells. To avoid spurious oscillations at regions where the gradients of the variable are considerable, advanced slope limiter functions are implemented in the numerical algorithm. The effects of bed slope, bed friction and turbulences are considered in the source terms. The bed slope and bed friction terms are computed using the data at the center of each cell. Three depth-averaged turbulence models, including the mixing length,k-ε, and algebraic stress model (ASM), are used to close the hydrodynamic equations. Some experiments are carried out in the ume of a hydraulic laboratory to examine the behavior of the oblique shock waves downstream of a side-baffle. The supercritical ow in the channel is then simulated numerically and results are compared with the experimental data. A comparison of the experimental results and numerical predictions confirm the robustness of the numerical model. In particular, implementation of turbulence models improves the results at the shock positions. Moreover, all of the models are able to simulate the vortex next to the baffle successfully. However, the k-ε model and the ASM demonstrate a stronger vortex pattern. Based on our overall findings, the ASM offer superior results to the other models. The quantitative error analysis confirms this finding as well. Our numerical experiments, however, revealed that amongst the source term components, the negligence of the turbulence terms produces the least relative depth error in comparison with the removal of the bed slope or bed friction terms.

Key words

finite volume method mixing length model k-ε model algebraic stress model oblique standing waves