scholarly journals Investigation of Wall Function and Turbulence Model Performance within the Wind Code

2005 ◽  
Author(s):  
Vance Dippold
Keyword(s):  
Turbulence Model ◽  
Model Performance ◽  
Wall Function

scholarly journals Evaluation of Turbulence-Model Performance in Jet Flows

AIAA Journal ◽  
2001 ◽  
Vol 39 (12) ◽  
pp. 2402-2404 ◽  
Author(s):  
S. L. Woodruff ◽  
J. M. Seiner ◽  
M. Y. Hussaini ◽  
G. Erlebacher
Keyword(s):  
Turbulence Model ◽  
Model Performance ◽  
Jet Flows

Assessment of Turbulence Model Performance Adopted Near Wall Treatment for a Sharp 90° 3-D Turning Diffuser

2017 ◽  
pp. 259-273
Author(s):  
Normayati Nordin ◽  
Zainal Ambri Abdul Karim ◽  
Safiah Othman ◽  
Vijay R. Raghavan ◽  
Sharifah Adzila ◽  
...  
Keyword(s):  
Turbulence Model ◽  
Model Performance ◽  
Near Wall

scholarly journals Prediction of Heat Transfer For Turbulent Flow in Rotating Radial Duct

1995 ◽  
Vol 2 (1) ◽  
pp. 51-58
Author(s):  
P. Tekriwal
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Reynolds Number ◽  
Turbulence Model ◽  
High Reynolds Number ◽  
Low Reynolds Number ◽  
Rotating Flows ◽  
Wall Function ◽  
Model Predictions ◽  
High Reynolds

The objective of the current modeling effort is to validate the numerical model and improve upon the prediction of heat transfer in rotating systems. Low-Reynolds number turbulence model (without the wall function) has been employed for three-dimensional heat transfer predictions for radially outward flow in a square cooling duct rotating about an axis perpendicular to its length. Computations are also made using the standard and extended high-Reynolds number kturbulence models (in conjunction with the wall function) for the same flow configuration. The results from all these models are compared with experimental data for flows at different rotation numbers and Reynolds number equal to 25,000. The results show that the low-Reynolds number model predictions are not as good as the high-Re model predictions with the wall function. The wall function formulation predicts the right trend of heat transfer profile and the agreement with the data is within 30% or so for flows at high rotation number. Since the Navier-Stokes equations are integrated all the way to wall in the case of low-Re model, the computation time is relatively high and the convergence is rather slow, thus rendering the low-Re model as an unattractive choice for rotating flows at high Reynolds number.The extended k-ε turbulence model is also employed to compute heat transfer for rotating flows with uneven wall temperatures and uniform wall heat flux conditions. The comparison with the experimental data available in literature shows that the predictions on both the leading wall and the trailing wall are satisfactory and within 5-25% agreement.

Capturing S-Shape of Pump-Turbines by CFD Simulations Using an Anisotropic Turbulence Model

2019 ◽  
Author(s):  
Ernesto Casartelli ◽  
Luca Mangani ◽  
Armando Del Rio ◽  
Angelika Schmid
Keyword(s):  
Turbulence Model ◽  
Electricity Market ◽  
Vortex Formation ◽  
Model Performance ◽  
Reynolds Stress Model ◽  
Market Demand ◽  
Operational Flexibility ◽  
Transient Conditions ◽  
Sst Turbulence Model ◽  
The Right

Abstract Pump-turbines cope very well with modern electricity-market demand, having high operational flexibility and storage capabilities. Nevertheless, dynamic operation of these machines can lead to very challenging transient conditions, depending on the shape of the characteristic. Mechanical integrity can be correspondingly affected. Therefore assessment of the characteristic during the design phase, i.e. before model testing, is of crucial importance. In the past years different attempts to accurately compute the characteristic under steady (i.e. fix point) and transient conditions have been undertaken using RANS CFD. While the SST turbulence model has become the reference for machine design, it often fails for conditions close to or around instabilities. Its strength to accurately predict separation close to sound conditions (i.e. mild part- and over-load) is no more helpful. Under unstable conditions, which are characterized by continuous unsteady vortex formation, turbulence isotropy as assumed by linear two equation models is no more the right choice. Accordingly a turbulence model able to capture anisotropy, EARSM (Explicit Algebraic Reynolds Stress Model), has been implemented in an in-house code and used for the computation of the characteristic of various machines, stable and unstable, in order to assess the model performance. In this paper computations of three different machines in turbine mode are presented. Results using steady boundary conditions (BC) in the unstable region as well as transient BC like load-rejection and runaway are computed with EARSM, showing its superiority compared to linear two equation models.

scholarly journals Evaluation of turbulence-model performance in jet flows

AIAA Journal ◽  
2001 ◽  
Vol 39 ◽  
pp. 2402-2404
Author(s):  
S. L. Woodruff ◽  
M. Y. Hussaini ◽  
G. Erlebacher ◽  
J. M. Seiner
Keyword(s):  
Turbulence Model ◽  
Model Performance ◽  
Jet Flows

On the Wall Boundary Condition for Computing Turbulent Heat Transfer With K–ω Models

2000 ◽  
Author(s):  
J. Bredberg ◽  
S.-H. Peng ◽  
L. Davidson
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Reynolds Number ◽  
Channel Flow ◽  
Turbulence Model ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Wall Function ◽  
Wall Boundary Condition ◽  
Wall Boundary

Abstract A new wall boundary condition for the standard Wilcox’s k–ω model (1988) is proposed. The model combines a wall function and a low-Reynolds number approach, and a function that smoothly blends the two formulations, enabling the model to be used independently of the location of the first interior computational node. The model is calibrated using DNS-data for a channel flow and applied to a heat transfer prediction for a flow in a rib-roughened channel (Reb = 100 000). The results obtained with the new model are improved for various mesh sizes and are asymptotically identical with those of the standard k–ω turbulence model.

Sign in / Sign up

Export Citation Format

Share Document