1. VIV frequency analysis

This data group is optional, default values will be inserted if the data group is not given.

1.1. Data group identifier, one input line

EIGEnvalue ANALysis PARAmeters

1.2. Number of eigenvalues and -vectors, one input line

NEIG

  • NEIG: integer, default: 10: Number of eigenvalues to be calculated

The number of eigenvalues and eigenvectors to be calculated is the total number of frequencies. Once these have been found the program selects the cross-flow or in-line frequencies as relevant. Approximately 50% of the calculated frequencies are in-line and 50% are cross-flow. This means that in order to study VIV response up to frequency no. 30, the user must specify NEIG >= 60.

1.3. Computation parameters, one input line

The parameters below correspond to Lanczos' method for solution of eigenvalue problems. For a detailed discussion, see Nour-Omid et al. or Parlett.

TOL MAXLAN

  • TOL: real >0, default: 1.0e-10: Maximum acceptable relative error in computed eigenvalues

  • MAXLAN: integer, default: 8+2*NEIG: Maximum number of Lanczos steps (vectors) to be used. Note that if specified MAXLAN >= 8+2*NEIG

1.4. Data group identifier, one input line

EIGEnvalue PRINt OPTIons

1.5. Print selection parameters, one input line

NPEIG NPVEC

  • NPEIG: integer, default: 0: Number of eigenvalues to be printed (≤ NEIG)

  • NPVEC: integer, default: 0: Number of eigenvectors to be printed (≤ NVEC)

    • = 0: All eigenvectors are printed