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TABS-MDS
PE CARD
CONTROL OF THE HORIZONTAL EDDY VISCOSITY
PE CARD
AND DIFFUSION COEFFICIENT BY PECLET NUMBER
Field
Variable
Value
Description
0,C1-2
IC1
PE
Card group identifier
0,C3
IC3
b/
Option 1: Universal asignment by node
T
Option 2: Assignment by material type.
0,1
1
IPEC
Option 1: On/Off switch for Peclet number control. IPEC = 1 turns
on Peclet number control.
Option 2: Material type for the Peclet parameter assignment.
+
NMAT
2
GPEC
+
Peclet number for turbulent exchange
3
GPECD
+
Peclet number for diffusion
4
VPEC
+
Velocity used to generate the minimum allowable turbulent exchange
and diffusion coefficients.
5
SFPEC
+
Scale factor used to find the isotropic values of the turbulent exchange
and diffusion coefficients. It defines the ratio of the isotropic values
to the directional values (see below). This ratio should be ≤ 1.
Note:
The instantaneous magnitude of the horizontal eddy viscosity is found
from the Peclet number according to the following formula:
E = ρ|V|dx/P
where E is the eddy viscosity, P is the Peclet number, ρ is the density
of water, |V| is the velocity magnitude, and dx is the characteristic
element length (which is the square root of the surface area of the
element).
The instantaneous direction of the eddy viscosity is in the direction of flow
The instantaneous magnitude of the horizontal diffusion coefficient is
found from the Peclet number according to the following formula:
D = |V|dx/P
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