1. BODY - Description of attached bodies

1.1. Data group identifier

NEW COMPonent BODY

1.2. Component type identifier

CMPTYP-ID

  • CMPTYP-ID: character(8): Component type identifier

A body is a component that may be attached at supernodes and segment interconnection points. The following essential properties should be observed:

  • The BODY is directly attached to a nodal point and has no motion degrees of freedom by itself.

  • The BODY component serves to add concentrated masses (inertia force), weight or buoyancy forces to the system.

1.3. Mass and volume

AM AE

  • AM: real: Mass \(\mathrm {[M]}\)

  • AE: real: Displacement volume \(\mathrm {[L^3]}\)

1.4. Hydrodynamic coefficients

ICOO CDX CDY CDZ AMX AMY AMZ

  • ICOO: character(5): Coordinate system code

    • ICOO=GLOBAL: Coefficients refer to global coordinate system

    • ICOO=LOCAL: Coefficients refer to local coordinate system of neighbour elements in the actual line

  • CDX: real: Drag force coefficient in X-direction \(\mathrm {[F/(L/T)^2)]}\)

  • CDY: real: Drag force coefficient in Y-direction \(\mathrm {[F/(L/T)^2)]}\)

  • CDZ: real: Drag force coefficient in Z-direction \(\mathrm {[F/(L/T)^2)]}\)

  • AMX: real: Added mass in X-direction \(\mathrm {[M]}\)

  • AMY: real: Added mass in Y-direction \(\mathrm {[M]}\)

  • AMZ: real: Added mass in Z-direction \(\mathrm {[M]}\)

The drag forces acting in the global/local coordinate system are computed as:

  • \(\mathrm {F_x=CDX\times VRELX\times VRELX}\)

  • \(\mathrm {F_y=CDY\times VRELY\times VRELY}\)

  • \(\mathrm {F_z=CDZ\times VRELZ\times VRELZ}\)

where:

  • \(\mathrm {CDX,CDY,CDZ}\): are the input drag force coefficients in global/local x, y and z-directions, respectively

  • \(\mathrm {VRELX,VRELY,VRELZ}\): are relative water velocities in global/local x, y and z-directions respectively

The input quadratic drag force coefficients \(\mathrm {CDX}\), \(\mathrm {CDY}\) and \(\mathrm {CDZ}\) will normally be calculated as:

  • \(\mathrm {CDX=\frac{1}{2}\rho B_xC_{dx}}\)

  • \(\mathrm {CDY=\frac{1}{2}\rho B_yC_{dy}}\)

  • \(\mathrm {CDZ=\frac{1}{2}\rho B_zC_{dz}}\)

where:

  • \(\mathrm {\rho }\): water density

  • \(\mathrm {B_x,B_y,B_z}\): projected area for flow in global/local y and z-direction

  • \(\mathrm {C_{dx},C_{dy},C_{dz}}\): nondimensional drag coefficients in global/local x, y and z-directions