1. VIVANA print flags

1.1. Data group identifier, one input line

VIVAna RESUlt PRINt

1.2. Print flags, one input line

IPRELF IPRSTF IPRDRG IPRRSP IPRCNG

  • IPRELF: integer, default: 1: Print flag for printing local element forces to the _vivana.res file.

    • IPRELF = 0: No print

    • IPRELF = 1: Print

  • IPRSTR: integer, default: 1: Print flag for printing local element stresses to the _vivana.res file.

    • Interpreted as IPRELF.

  • IPRDRG: integer, default: 1: Print flag for printing drag amplification factor to the _vivana.res file. Some drag amplification results will be stored on the _vivana.mpf file regardless of this option. See below for details.

    • Interpreted as IPRELF.

  • IPRRSP: integer, default: 1: Print flag for printing VIV response (displacements) to the _vivana.res file.

    • Intepreted as IPRELF.

  • IPRCNG: integer, default: 1: Print flag for printing convergence during the response analysis to the _vivana.res file.

    • Interpreted as IRRELF.

For cross-flow VIV loading the drag amplification will be calculated using two methods:

  • Blevens’s formula (method 1) : the drag amplification is calculated from the cross-flow response amplitude for each response frequency. These drag amplification factors are written to the _vivana.res file if IPRDRG = 1 and are not available if IPRDRG = 0.

  • Vandiver’s formula (method 2): the drag amplification is calculated from the standard deviation of the cross-flow response. These drag amplification factors are written to the _vivana.res file if IPRDRG =1. They are always written to the _vivana.mpf file.

For in-line VIV loading the drag amplification is calculated for each response frequency using the in-line response amplitude to interpolate in Aronsen’s data. These drag amplification factors are written to the _vivana.res file if IPRDRG =1. They are always written to the _vivana.mpf file.

For combined cross-flow and in-line VIV loading the drag amplification is calculated in the same two ways as for cross-flow loading. Note that this uses the cross-flow response only at the cross-flow response frequencies. The calculated drag amplification will therefore NOT be influenced by the in-line VIV loading!