scholarly journals Prediction Capability of Cartesian Cut-Cell Method with a Wall-Stress Model Applied to High Reynolds Number Flows

2020 ◽  
Vol 10 (15) ◽  
pp. 5050
Author(s):  
Yuki Takeda ◽  
Kazuyuki Ueno ◽  
Tatsuya Ishikawa ◽  
Yuta Takahashi
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Wall Stress ◽  
Stress Model ◽  
Cell Method ◽  
Cut Cell ◽  
Cell Simulation ◽  
High Reynolds ◽  
Cartesian Cut ◽  
Reynolds Number Flows

The Cartesian cut-cell method is one of the most promising methods for computational fluid dynamics due to its sharp interface treatment. However, the Cartesian cut-cell method and other Cartesian mesh solvers have difficulty with concentrating grid to boundary layers. The wall-modelling of shear stress is one of the most effective methods to reduce computational grids in boundary layers. This study investigated the applicability of a wall-stress model to the Cartesian cut-cell method. In the numerical simulations of the flow around a triangular column, Cartesian cut-cell simulation with the wall-stress model adequately predicted the drag coefficient. In the numerical simulations of the flow around a 30P30N high-lift airfoil configuration, the Cartesian cut-cell simulation with the wall-stress model adequately predicts the lift coefficient. The intermittent vortex structure of the outer layer of the turbulent boundary layer was observed on the suction side of the main element and the flap. The Cartesian cut-cell method with a wall-stress model is useful for predicting high Reynolds number flows at R e ∼ 10 6 .

Simple and Robust Cut-Cell Method for High-Reynolds-Number-Flow Simulation on Cartesian Grids

AIAA Journal ◽  
2017 ◽  
Vol 55 (8) ◽  
pp. 2833-2841 ◽  
Author(s):  
Motoshi Harada ◽  
Yoshiharu Tamaki ◽  
Yuichi Takahashi ◽  
Taro Imamura
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Flow Simulation ◽  
Cartesian Grids ◽  
Cell Method ◽  
Reynolds Number Flow ◽  
Cut Cell ◽  
Number Flow ◽  
High Reynolds

Prediction of Vortex Shedding From a High Reynolds Number Airfoil Using LES With and Without Wall Model

2006 ◽  
Author(s):  
Peter A. Chang ◽  
Meng Wang ◽  
Jonathan Gershfeld
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Turbulent Boundary Layer ◽  
Vortex Shedding ◽  
High Reynolds Number ◽  
Wall Stress ◽  
Wall Pressure ◽  
Pressure Side ◽  
Stress Model ◽  
High Reynolds

ATTACHED, wall-bounded flows impose computational requirements on LES that increase drastically with Reynolds number. For that reason, even simple geometries, such as airfoils at small angles of attack, with spanwise uniform section shape, challenge the bounds of LES as chord-based Reynolds numbers increase much above 1 million. Of particular concern is the ability of LES to predict the occurrence, and strength of, weak vortex shedding from the airfoil trailing edge (by weak vortex shedding we mean that the acoustic vortex shedding signature may rise only a few decibels above that for the broadband turbulent boundary layer acoustic sources). Correct prediction of weak vortex shedding may depend on accurately predicting the flow over the entire airfoil that includes the attached, turbulent upstream flow, adverse pressure gradient and separated flow regions and finally, the turbulent wake. This paper compares results of two full-LES and two LES with wall-stress model for the flow about a modified NACA 0016 airfoil with a 41° trailing edge apex angle and a slightly convex pressure side. Comparisons of vortex shedding, as measured by the power spectral density (PSD) of wall pressure fluctuations (WPF) on the pressure side of the TE and the PSD of the vertical velocity fluctuations in the wake are made. The results indicate that vortex shedding predictions are dependent upon the stream-wise and spanwise grid resolution. In order to reduce the large computational times required for simulating the high-Reynolds number flows with fully-resolved LES, a wall-stress model that solves the turbulent boundary layer equations in the near-wall region is applied. Compared with the fully-resolved LES, the LES with wall-stress simulations require about 20 percent the number of grid points and require about 10 percent of the computational time. However, the LES with wall stress model results under-predict the vortex shedding peak in the wake and are not able to predict the vortex shedding signature in TE wall pressure spectra. These results indicate that near-wall turbulence structures need to be resolved in order to correctly predict the occurence and strength of vortex shedding.

Modeling and Simulation of High Reynolds' Number Flows During Reaction Injection Mold Filling

1994 ◽  
Vol 9 (3) ◽  
pp. 279-285 ◽  
Author(s):  
Rahima K. Mohammed ◽  
Tim A. Osswald ◽  
Timothy J. Spiegelhoff ◽  
Esther M. Sun
Keyword(s):  
Reynolds Number ◽  
Modeling And Simulation ◽  
High Reynolds Number ◽  
Mold Filling ◽  
Injection Mold ◽  
High Reynolds ◽  
Reynolds Number Flows

Immersed Methods for High Reynolds Number Fluid-Structure Interactions

2017 ◽  
Vol 14 (06) ◽  
pp. 1750068 ◽  
Author(s):  
Lucy T. Zhang
Keyword(s):  
Finite Element Method ◽  
Reynolds Number ◽  
Finite Element ◽  
High Reynolds Number ◽  
Fluid Structure Interactions ◽  
Immersed Finite Element Method ◽  
Immersed Finite Element ◽  
High Reynolds ◽  
Immersed Methods ◽  
Reynolds Number Flows

Immersed methods are considered as a class of nonboundary-fitted meshing technique for simulating fluid–structure interactions. However, the conventional approach of coupling the fluid and solid domains, as in the immersed boundary method and the immersed finite element method, often cannot handle high Reynolds number flows interacting with moving and deformable solids. As the solid dynamics is imposed by the fluid dynamics, it often leads to unrealistically large deformation of the solid in cases of high Reynolds number flows. The first attempt in resolving this issue was proposed in the modified immersed finite element method (mIFEM), however, some terms were determined heuristically. In this paper, we provide a full and rigorous derivation for the mIFEM with corrections to the previously proposed terms, which further extends the accuracy of the algorithm. In the “swapped” coupling logic, we solve for the dynamics of the solid, and then numerically impose it to the background fluid, which allows the solid to control its own dynamics and governing laws instead of following that of the fluid. A few examples including a biomedical engineering application are shown to demonstrate the capability in handling large Reynolds number flows using the derived mIFEM.

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