Optimized cross flow transition model for Reynolds Averaged Navier Stokes applications

In Reynolds-Averaged Navier Stokes (RANS) models simplifying assumptions breakdown in near wall regions. Wall functions/treatments become inaccurate and the homogeneity and isotropy models may not hold. To see the effect that these assumptions have on the validity of boundary layer results in a commercially available RANS code, key boundary layer parameters are compared from laminar, transitional, and fully turbulent RANS results to an existing direct numerical simulation (DNS) simulation for flow over a flat plate with an adverse pressure gradient (APG). Parameters compared include velocity profiles in the free stream, boundary layer thicknesses, skin friction coefficient and the pressure gradient parameter. Results show comparable momentum thickness and pressure gradient parameters between the transition RANS model and the DNS simulation. Differences in the onset of transition between the RANS transition model and DNS are compared as well. These simulations help evaluate the models used in the RANS code. Of most interest is the transition model, a transition shear-stress transport (SST) k–omega model. The RANS code is being used in conjunction with an APG boundary layer experiment being undertaken at the Idaho National Laboratory (INL).

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Numerical investigation of vortex-induced vibration of an elastically mounted circular cylinder with One-degree of freedom at high Reynolds number using different turbulent models

Proceedings of the Institution of Mechanical Engineers Part M Journal of Engineering for the Maritime Environment ◽

10.1177/1475090217751992 ◽

2018 ◽

Vol 233 (2) ◽

pp. 443-453 ◽

Cited By ~ 4

Author(s):

Niaz Bahadur Khan ◽

Zainah Ibrahim

Keyword(s):

Reynolds Number ◽

Flow Direction ◽

Cross Flow ◽

Navier Stokes ◽

Two Dimensional ◽

Detached Eddy Simulation ◽

Eddy Simulation ◽

Flow Around Cylinder ◽

Reynolds Averaged Navier Stokes ◽

Turbulent Models

This study presents numerical investigation for flow around cylinder at Reynolds number = 104 using different turbulent models. Numerical simulations have been conducted for fixed cylinder case at Reynolds number = 104 and for cylinder free to oscillate in cross-flow direction, at Reynolds number O (104), mass–damping ratio = 0.011 and range of frequency ratio wt = 0.4–1.4 using two-dimensional Reynolds-averaged Navier–Stokes equations. In the literature, the study has been conducted using detached eddy simulation, large eddy simulation and direct numerical simulation which are comparatively expensive in terms of computational cost. This study utilizes the Reynolds-averaged Navier–Stokes shear stress transport k-ω and realizable k-ε models to investigate the flow around fixed cylinder and flow around cylinder constrained to oscillate in cross-flow direction only. Hydrodynamic coefficients, vortex mode shape and maximum amplitude ( Ay/ D) extracted from this study are compared with detached eddy simulation, large eddy simulation and direct numerical simulation results. Results obtained using two-dimensional Reynolds-averaged Navier–Stokes shear stress transport k-ω model are encouraging, while realizable k-ε model is unable to capture the entire response branches. In addition, broad range of “lock-in” region is observed due to delay in capturing the transition from upper to lower branch during two-dimensional realizable k-ε analyses.

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Experimental and numerical analyses of gas–solid-multiphase jet in cross-flow

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410011429420 ◽

2012 ◽

Vol 227 (1) ◽

pp. 61-79 ◽

Cited By ~ 2

Author(s):

Yao Fu ◽

Tong Wang ◽

Chuangang Gu

Keyword(s):

Flow Field ◽

Transient Flow ◽

Cross Flow ◽

Jet Flow ◽

Navier Stokes ◽

Detached Eddy Simulation ◽

Calculation Methods ◽

Mean Flow ◽

Eddy Simulation ◽

Reynolds Averaged Navier Stokes

In this article, jet influence on a gas–solid-multiphase channel flow was experimentally and numerically studied. The jet flow was found to have a diameter-selective controlling effect on the particles’ distribution. Jet flow formed a gas barrier in the channel for particles. While tiny particles could travel around and large particles could travel through, only particles on the 10 -µm scale were obviously affected. Three different calculation methods, Reynolds averaged Navier–Stokes, unsteady Reynolds averaged Navier–Stokes, and detached eddy simulation, were used to simulate this multiphase flow. By comparing the calculation results to the experimental results, it is found that all the three calculation methods could capture the basic phenomenon in the mean flow field. Nevertheless, there exist great differences in the transient flow field and particle distribution.

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