This data category is used to input or change the wave frequency dependent hydrodynamic parameters and the linear hydrostatic stiffness matrix of one or more structures. All parameters, except the hydrostatic stiffness, are associated with the frequencies and directions input in the previous data category (Data Category 6). Values of added mass, and radiation damping may be input for each frequency. Values of diffraction forces, Froude Krylov forces and response amplitude operators (RAOs) may be input for each frequency and for each direction.

Although this data category is applicable to all programs using the hydrodynamic parameters this data category is only used when:

(a) the backing file produced by a previous Aqwa-Line run, containing the values of the parameters, is not available; in other words, Aqwa-Line has not been run previously, or you wish to input values of the parameters obtained from a source other than Aqwa-Line.

or

(b) you wish to change some of the values or append to some of the values calculated by a previous Aqwa-Line run for the current analysis (Aqwa-Fer/ Drift/Librium/Naut) or within the backing file (Aqwa-Line only).

The normal mode of operation of the programs using the hydrodynamic parameters is to read these values from the backing file of a previous Aqwa-Line run. Therefore, unless (a) or (b) above apply, you should omit this data category by entering NONE for the data category keyword (see Compulsory Data Category Keyword).

3. Default Values when Omitting Data Records

With the exception of the specification of frequency and direction, which are required for the input of parameters dependent on these variables, the omission of any data record in this data category will result in the existing values being unchanged. Any data record in this data category whose values are all zero in columns 21-80, and which does not overwrite existing values is redundant and may be omitted.