Define Objects: Forces


Define Objects: Surfaces| Volumes| Components| Bodies| Forces

User-defined forces allow the application of known forces on a body under control of the SIXDOF model. The effects of the forces given here are simply added to the forces and moments arising from the flowfield around the body. Note that moments are added to the body appropriately by the solver, since the forces specified below act at a given point (which is used to compute a moment arm to the body CG).


Impulse


Impulse Force 		An impulse force is applied at a specific elapsed time and for a specific duration.

The format for the impulse force definition is given below: 

force 1: impulse 
    body = # 
    magnitude = #
    direction = (# # #)
    point = (# # #)
    time = #
    dt = #
    frame = [relative|absolute];

The "body" parameter specifies body to which to apply the extra force. The magnitude and direction of the force vector must be specified, as well as the point at which the force is applied. The impulse will be applied from "time" to "time + dt".

The "frame" flag denotes whether or not the force direction and location of application should be carried with the body (relative) or set to an unchanging point in space (absolute). If relative, the direction and point given correspond to the body position at time t=0.

Example: 
force 1 [name=Plane]: impulse
    body = 1 
    magnitude = 1.2 
    direction = (0.0 -1.0 0.0)
    point = (1.2 4.3 2.1)
    time = 0.003 
    dt = 0.0001 
    frame = relative;



Sustained


Sustained Force 		A sustained force is applied for all time.

The format for the sustained force definition is given below: 

force 1: sustained
    body = #
    magnitude = #
    direction = (# # #)
    point = (# # #)
    frame = [relative|absolute];

The "body" parameter" specifies body to which to apply the extra force. The magnitude and direction of the force vector must be specified, as well as the point at which the force is applied.

The "frame" flag denotes whether or not the force direction and location of application should be carried with the body (relative) or set to an unchanging point in space (absolute). If relative, the direction and point given correspond to the body position at time t=0.

Example: 
force 1 [name=Plane]: sustained
    body = 1
    magnitude = 1.2
    direction = (0.0 -1.0 0.0)
    point = (1.2 4.3 2.1)
    frame = relative;

For further information related to the materials in this web site, USS_U2NCLE, U2NCLE,  SolidMesh, DIVA or information related to their use, please contact:

David L. Marcum
marcum@erc.msstate.edu

Phone: (662) 325-3193,   FAX: (662) 325-7692

Computational Simulation and Design Center
Engineering Research Center for Computational Field Simulation
Mississippi State University
Box 9627, Mississippi State, MS  39762

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