VIV Drag |
 
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VIV Drag |
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This section describes a facility whereby vortex-induced vibration (VIV) drag coefficient amplification factors may be read from the results of a Shear7 analysis.
Flexcom provides an option to allow vortex-induced vibration (VIV) drag coefficient amplification factors to be read from the results of a Shear7 analysis. If this option is invoked, the relevant inputs are the name of the Shear7 analysis from which drag amplification factors are to be read, and the set of elements to which these factors are to be applied.
How this capability operates is as follows. When computing current forces, Flexcom loops over all elements in the nominate element set. For a given integration point, the program finds the drag amplification factor output for the nearest points in the Shear7 data, and then calculates a value for the integration point by linear interpolation. This factor then multiplies the user-specified drag coefficient when the current force for the integration point is being found via Morison’s Equation.
•*CURRENT is used to specify current loading.
•*VIV DRAG is used to instruct Flexcom to read vortex-induced vibration (VIV) drag coefficient amplification factors from the results of a Shear7 analysis.
If you would like to see an example of how these keywords are used in practice, refer to A04 - TTR Wake Interference.