Disturbed Wave Field A disturbed wave field gives the wave kinematics around a large floating body that diffracts and shields the incident waves. When a disturbed wave field is defined, slender elements and fixed body elements inside a defined box-shaped region discretized by a regular grid of field points are exposed to the disturbed (diffracted and radiated) wave kinematics around the diffracting hull instead of the undisturbed Airy kinematics. This is useful for operations in the shadow zone of a vessel — for example a module lowered through the splash zone on the sheltered side of a crane vessel — where shielding can reduce the wave loads significantly. The disturbed wave field is calculated by a potential theory program such as WADAM and imported into SIMA. It is defined by: Wave field file: the HDF5 (*.h5) database holding the diffracted wave elevation and velocity transfer functions for the regular grid of field points around the diffractor. Diffractor body: the body whose hull diffracts and shields the waves. Field points and wave headings are interpreted relative to this body. Number Of Headings: the number of relative wave headings the shielding field is interpolated over. The default is 36, i.e. a heading resolution of 10 degrees. The wave radiation part of the disturbed wave field is dependent on the motion transfer function (RAO) computed by the potential theory program (e.g. WADAM). It is therefore important that these motion transfer functions are representative for the actual wave-frequency motions of the diffractor body in the simulation. 1. Importing a disturbed wave field A disturbed wave field is created by importing a WADAM SIF file that contains wave-kinematics data. On import the wave field is written to an HDF5 database and a disturbed wave field referencing it is added to the SIMO model. For a single-body model the diffractor body is set automatically. Wave Radiation Forces Couplings