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9.2. List of the low-Re models available in PHOENICS

PHOENICS makes provision for the following low-Reynolds-number turbulence models:

  1. the Lam-Bremhorst low-Re extension to the KE-EP model;
  2. the two-layer low-Re KE-EP model;
  3. the Wilcox low-Re extension to the KE-OMEG model;
  4. the Van-Driest low-Re damping model for the length scale; and
  5. an algebraic eddy viscosity model based on the solution of a generalised turbulent-length-scale variable LTLS and Spalding's

In addition, two options are provided for the turbulent viscosity to be modified by multiplication by a factor which is a function of the local Reynolds number of turbulence.

This feature, here called LRNM (standing for Local Reynolds Number Modification), is provided in subroutine GXENUT, where it is activated by setting IENUTA = 6 or 9.

The LRNM turbulent-viscosity formula for INEUTA=6 is:

vist = vist_nom * amin1(1.0 , (A * vist_nom/visl) ** B)

    where:  (vist_nom/visl) is the Local Reynolds Number (LRN)
            vist     = turbulent kinematic viscosity to be used
            vist_nom = nominal (high-Reynolds-number) value of vist
            visl     = laminar viscosity
            A        = ENUTA
            B        = ENUTB

Suitable values for A and B may be 0.05 and 4.0.

The LRNM turbulent-viscosity formula for INEUTA=9 is:

vist = vist_nom for ENUTA * LRN < 1.0, and vist = 0.0 for ENUTA * LRN < 1.0

A suitable value for ENUTA may be 0.05 .

Relevant "help-file" entries are :- DISWAL, EL1, EL1A, EL2, EL2A, ENUT, ENUTA, GENK, PRT, TURBUL, TURMOD.

Relevant "Encyclopaedia" entries include: CHEN-Kim KE-EP turbulence model, K-Omega turbulence model, LAM-Bremhorst KE-EP turbulence model, LVEL turbulence model, RNG KE-EP turbulence model, TWO-Layer KE-EP turbulence model, VAN-Driest damping model.