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BL_INIT - Boundary layer initialization
Structured Grids
BL_INIT nb ixs str igrs [delt] nbli nzone
|
For ideal gases (i.e., no CHEMISTRY)
and structured grids, the BL_INIT keyword may be used to
initialize a j or k boundary with a laminar or turbulent
flat plate boundary layer.
Providing a better initial guess in these tightly clustered
(and time step limiting) near-wall regions can yield faster
convergence. Historically, this option was used on slower
computer systems, but is rarely used today.
The user-specified values are defined as:
| nb |
| A number from 1 to 4 indicating which boundary to initialize
|
1 | | for j = 1
|
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|
2 | | for j = jmax
|
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|
3 | | for k = 1
|
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|
4 | | for k = kmax
|
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|
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| ixs |
| Integer indicating method for specifying the axial location
to start the boundary layer:
|
1 | | to specify the i index
|
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|
2 | | to specify the x station
|
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|
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| str |
| i index or x location to start the
boundary layer, depending on the value of ixs
|
---|
| igrs |
| Integer indicating method for specifying the initial height of
the boundary layer:
|
1 | | to specify the number of grid points from the wall
|
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|
2 | | to specify the thickness
|
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|
3 | | to compute thickness from initial x station
|
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|
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| delt |
| Number of grid points in boundary layer (if igrs = 1),
or boundary layer thickness (inches) (if igrs = 2)
|
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| nbli |
| Integer indicating type of boundary layer and whether to keep
constant thickness or grow with x
|
1 | | Turbulent profile, growing with x
|
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|
−1 | | Turbulent profile, constant thickness
|
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|
2 | | Laminar profile, growing with x
|
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|
−2 | | Laminar profile, constant thickness
|
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|
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| nzone |
| Zone number for initialization
|
0 | | All zones
|
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|
> 0 | | Zone nzone only
|
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|
A flat plate temperature distribution will also be constructed
consistent with the wall temperature boundary condition of either
adiabatic or constant temperature wall, as specified using the
WALL TEMPERATURE keyword.
However, this keyword cannot be used with WALL TEMPERATURE
EQUILIBRIUM.
Note: BL_INIT cannot currently do more than one boundary
in each zone without over-writing itself.
Last updated 18 Dec 2006