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*Viscous Drag |
 
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*Viscous Drag
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*Viscous Drag |
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To define viscous drag for a floating body.
Refer to Viscous Damping Coefficients for further information on this feature.
Block of data consisting of the floating body name followed by the viscous drag definition. The viscous drag matrix is defined by a block of 6 lines, preceded by a single line which specifies the velocity type used for calculation of viscous forces. The entire block of data can then be repeated to specify viscous drag for second and subsequent floating bodies.
Line defining floating body name:
FLOATING BODY=Floating Body Name
Line defining viscous drag type:
TYPE=MATRIX
Line defining velocity type used for calculation of viscous forces:
OPTION=ABSOLUTE/RELATIVE
Block of lines defining viscous drag matrix:
V11, V12, V13, V14, V15, V16
V21, V22, V23, V24, V25, V26
V31, V32, V33, V34, V35, V36
V41, V42, V43, V44, V45, V46
V51, V52, V53, V54, V55, V56
V61, V62, V63, V64, V65, V66
Input: |
Description |
Floating Body: |
The name of the floating body. |
Velocity Type: |
This option allows you to specify the type of velocity to be used in the calculation of viscous drag forces. The options are the Absolute velocity of the floating body (default) or the Relative velocity between the floating body and the external fluid. |
Viscous Drag: |
The name of the Absolute or Relative velocity viscous drag matrix definition. |
(a)The viscous drag matrix which you refer to for a particular floating body must be defined in the Body - Viscous Drag Coefficients table.
Input: |
Description |
Name: |
The name of the viscous drag coefficient matrix. |
Matrix (6x6): |
A 6x6 matrix of viscous drag coefficient data. See Note (a). |
(a)The layout of the viscous drag coefficient terms is as follows.
V11, V12, V13, V14, V15, V16
V21, V22, V23, V24, V25, V26
V31, V32, V33, V34, V35, V36
V41, V42, V43, V44, V45, V46
V51, V52, V53, V54, V55, V56
V61, V62, V63, V64, V65, V66
Each input corresponds to a viscous damping coefficient times an appropriate area term related to the dimensions of the floating body. For example, V11 is the viscous damping coefficient in surge times the projected floating body area in the local surge direction.