VIV Drag |
 
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VIV Drag |
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You may optionally specify that the drag coefficients you defined (in term of standard hydrodynamic properties) are to be amplified, based on the results of an analysis with the VIV program Shear7. This enables you to model the increase in drag that VIV typically causes.
There are two inputs, one mandatory, when you want to include so-called VIV Drag in a Flexcom analysis with current. The first (mandatory) input is the name of the Shear7 analysis from the results of which you want Flexcom to read drag amplification factors. The second (optional) input is the name of the set of elements to which you want these amplification factors to be applied; this defaults to all elements. How this capability operates is as follows. When computing current forces, Flexcom loops over all elements in the set you nominate. 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.
•*VIV DRAG is used to instruct Flexcom to read vortex-induced vibration (VIV) drag coefficient amplification factors from the results of a Shear7 analysis.