UFR 4-08 Best Practice Advice: Difference between revisions
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The best practice advice is based on the only known and available numerical computation performed by Wang (1991). | The best practice advice is based on the only known and available numerical computation performed by Wang (1991). | ||
=== Key Physics === | |||
* turbulent flow with streamline curvature, axi-symmetric separation and flow re-attachment | * turbulent flow with streamline curvature, axi-symmetric separation and flow re-attachment | ||
=== Numerical Modelling Issues === | |||
* an two-dimensional axi-symmetric calculation captures the main features of the flow | * an two-dimensional axi-symmetric calculation captures the main features of the flow | ||
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* the computational domain needs to insure a long enough inflow and outflow region | * the computational domain needs to insure a long enough inflow and outflow region | ||
=== Physical Modelling === | |||
* the standard k-ε turbulence model with wall functions can provide a reasonable good prediction of the turbulent kinetic energy field | * the standard k-ε turbulence model with wall functions can provide a reasonable good prediction of the turbulent kinetic energy field | ||
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* the result for mean velocities and turbulence intensities seems to be quite sensitive to the specification of the dissipation rate at the inlet cross-section | * the result for mean velocities and turbulence intensities seems to be quite sensitive to the specification of the dissipation rate at the inlet cross-section | ||
=== Recommendation for Future Work === | |||
* the application of a full Reynolds stress turbulence model should be able also to predict the anisotropy of the turbulence and will also allow to predict the shear stresses | * the application of a full Reynolds stress turbulence model should be able also to predict the anisotropy of the turbulence and will also allow to predict the shear stresses | ||
Revision as of 10:16, 9 March 2009
Orifice/deflector flow
Underlying Flow Regime 4-08 © copyright ERCOFTAC 2004
Best Practice Advice
Best Practice Advice for the UFR
The best practice advice is based on the only known and available numerical computation performed by Wang (1991).
Key Physics
- turbulent flow with streamline curvature, axi-symmetric separation and flow re-attachment
Numerical Modelling Issues
- an two-dimensional axi-symmetric calculation captures the main features of the flow
- a grid with 128x28 cells with a refinement near the orifice allowed an accurate prediction of the re-attachment length
- a second order scheme for the diffusion terms and a hybrid scheme for the convective terms is advisable
- the computational domain needs to insure a long enough inflow and outflow region
Physical Modelling
- the standard k-ε turbulence model with wall functions can provide a reasonable good prediction of the turbulent kinetic energy field
- the result for mean velocities and turbulence intensities seems to be quite sensitive to the specification of the dissipation rate at the inlet cross-section
Recommendation for Future Work
- the application of a full Reynolds stress turbulence model should be able also to predict the anisotropy of the turbulence and will also allow to predict the shear stresses
© copyright ERCOFTAC 2004
Contributors: Martin Sommerfeld - Martin-Luther-Universitat Halle-Wittenberg