MOVING [WALL] region \ {TRANSLATE {I speed | {X|Y|Z} speed | u v w} | \ SPIN {{X|Y|Z} ω c_{1} c_{2} | \ x_{c} y_{c} z_{c} {ANGLES θ φ ψ | AXIS ω x_{a} y_{a} z_{a}}} | \ TANGENT_ONLY} |
This keyword may be used to define a translating and/or spinning no-slip wall. Moving walls are activated in regions specified as bleed in the .cgd file (set with GMAN), where region is the "bleed" region number.
There are three options for specifying a translating wall.
TRANSLATE I | Wall is moving in the i direction at the velocity speed, in feet per second. This is only available for structured grids. | ||
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TRANSLATE {X|Y|Z} | Wall is moving in physical space in the x, y, or z direction at the velocity speed, in feet per second. | ||
TRANSLATE u v w | Wall is moving in physical space, where u, v, and w are the velocities in the x, y, and z directions, in feet per second. |
There are two options for specifying a spinning wall.
SPIN {X|Y|Z} ω c_{1} c_{2} | Wall is spinning in physical space about the x-, y-, or z-axis, with rotation rate ω in degrees per second. For rotation about the x-axis, c_{1} and c_{2} are the coordinates of the center of rotation in the yz-plane. Similarly, for rotation about the y-axis, they're the coordinates of the center of rotation in the xz-plane, and for rotation about the z-axis, they're the coordinates of the center of rotation in the xy-plane. | ||
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SPIN x_{c} y_{c} z_{c} {...} | Wall is spinning in physical space, with the coordinates x_{c}, y_{c}, and z_{c} defining the center of rotation. The rate and direction of rotation may be specified using either the ANGLES or AXIS keyword. For ANGLES, θ, φ, and ψ specify the rotation rates about the x-, y-, and z-axes, in degrees per second. For AXIS, ω is the rotation rate in degrees per second, and x_{a}, y_{a}, and z_{a} are the x, y, and z coordinates that, along with x_{c}, y_{c}, and z_{c}, define the axis of rotation. |
Separate MOVING WALL keywords may be used to specify a single region that is both translating and spinning in physical space. The TRANSLATE I option, however, may not be specified for a region that is also moving in physical space.
An additional MOVING WALL keyword specifying TANGENT_ONLY may be used to force the flow to be tangential to the wall by removing the normal velocity components. Note that this only makes sense if a separate MOVING WALL keyword (or keywords) is used to specify a translating and/or spinning wall.
Last updated 1 Apr 2016