Hydrodynamic Interaction Between Bodies

This option enables the user to include hydrodynamic interaction effects between an arbitrary number of bodies.

See description here

1 input line

HYDRodynamic COUPling DATA

1 input line

CHCPL

  • CHCPL: character(8): Hydrodynamic coupling identifier, must be unique

2 input lines

TEXT

  • TEXT: character(60): Character string

1 input line

CHBDY_A

  • CHBDY_A: character(8): Body identification for body A

1 input line

CHBDY_B

  • CHBDY_B: character(8): Body identification for body B

Note that the body data for CHBDY_A and CHBDY_B must precede the hydrodynamic coupling data for the two bodies.

1. Coupled added mass data

1 input line

COUPled ADDEd MASS

6 input lines

AMi1  AMi2  AMi3  AMi4  AMi5  AMi6

  • AMij: real: An acceleration of body A in dof i will be multiplied with AMij to give a force on body B in dof j, and an acceleration of body B in dof j will be multiplied with AMij to give a force on body A in dof i \(\mathrm {[M,ML,ML^2]}\)

2. Coupled retardation function

1 input line

COUPled RETArdation FUNCtion

1 input line

TIMDEL

  • TIMDEL: real: Time step in retardation function

1 input line

RETArdation ELEment DATA

1 input line

NRETij  IDOF_A  IDOF_B

  • NRETij: integer: Number of time delays for which function is given for element (IELEM, JELEM)

  • IDOF_A: integer: Degree of freedom body A

  • IDOF_B: integer: Degree of freedom body B

The velocity of body A degree of freedom IDOF_A will be convoluted with the retardation function to give a force/moment at body B in degree of freedom IDOF_B and

the velocity of body B degree of freedom IDOF_B will be convoluted with the retardation function to give a force/moment at body A in degree of freedom IDOF_A.

1 input line (continue by continuation mark &)

RETij(1)........RETij(NRETij)

  • RETij(k): real: Retardation function value \(\mathrm {[F/L,FT,FL]}\)