WIND User's Guide - Keyword Reference, MARCHING

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MARCHING - Parabolized Navier-Stokes algorithm

MARCHING [LIMITER value] [CHECKPOINT interval] [COPY]

This keyword enables WIND's spatial marching, or parabolized Navier-Stokes (PNS), algorithm for flowfields which are supersonic in the computational i-direction. In this mode, WIND marches from the i = 1 to the i = i_max computational surface, attempting to compute a steady-state solution at each plane before moving on to the next one. Using the PNS algorithm significantly reduces the computing time required for supersonic solutions.

LIMITER value This keyword enables the marching limiter, which limits the change in the solution vector Q to (value)Q. I.e.,
Delta Q <= (value)Q

CHECKPOINT interval The parameter interval specifies the number of i-planes to be computed before writing the current flowfield to the solution file. The default is 10.
COPY This keyword requests that WIND copy the solution from the most recently computed i-plane to the upcoming i-plane, giving a (hopefully) better initialization to the new i-plane than simply starting from freestream flow.

Notes

Marching is only available when WIND is run in serial mode.
Marching is not available with the one-equation turbulence models (BARTH, SPALART).
Marching requires that one of the following explicit operators be used. (See the RHS keyword.)
- Coakley (any order)
- Roe (first-order upwind, second-order upwind, third-order upwind-biased, first-order upwind modified for stretched grids, or second-order upwind-biased modified for stretched grids)
- Van Leer (first-order upwind, second-order upwind, or third-order upwind-biased)
The Roe, Van Leer, and HLLE second-order upwind-biased explicit operators modified for stretched grids use the i + 1 grid point, which is invalid in a PNS solution. When these operators are used, WIND automatically changes to first order in the i-direction.

See Also: RHS, TURBULENCE

	`LIMITER` value		This keyword enables the marching limiter, which limits the change in the solution vector Q to (value)Q. I.e., Delta Q <= (value)Q
	`CHECKPOINT` interval		The parameter interval specifies the number of i-planes to be computed before writing the current flowfield to the solution file. The default is 10.
	`COPY`		This keyword requests that WIND copy the solution from the most recently computed i-plane to the upcoming i-plane, giving a (hopefully) better initialization to the new i-plane than simply starting from freestream flow.