Page 56 - TransAT_Tutorial_Manual

TransAT Tutorial Manual 2.1. Block Mesh Refinement: Flow over Cylinder (Re=150)

Simulation Parameters
The Simulation Parameters tab is used to define the numerical parameters of the simulation.

• Click Simulation Parameters on the left-hand side of the TransATUI

• Set the following parameters to solve for an unsteady flow with an implicit method.
Simulation Type : Unsteady

Total simulation time : 10000
Max Number of Time Steps : 4000
I n i t i a l time step : 1.0
Max number of i t e r a t i o n s per timestep : 20

Autorelaxation : ON
Relaxation Factor : 0.83

A lower relaxation factor means a more stable simulation, a higher value means a faster
convergence.

• For Time Stepping select Adaptive then click

• Set the following parameters in the Adaptive Time-Stepping window then click to save
the settings and close the window

CFL Limits Min : 0.5 Max: 1.0
D i ff u s i o n Min : 1.0 Max: 2.0

Equations
In this section the convergence threshold is defined, as well as the convection scheme and the
solvers to be used by TransAT.

• Select All Quantities in the equation tree and set the value of Convergence Tolerance as
follows:
Convergence Tolerance : 1.0 e−3

• Select Other Variables in the equation tree and set the value of BMR Iterations as follows:
BMR I t e r a t i o n s : 5

• Select Pressure in the equation tree and set the value of BMR Iterations as follows:

BMR I t e r a t i o n s : 15

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