This data record is used to specify the direction to which the following diffraction forces, Froude Krylov forces or response amplitude operators, relate. The direction specified is operative until another DIRN data record is input. (NB See also the note at the end of this section when using Aqwa-Line.
2 5 7 11 16 21
- --- -- ---- ----- ----- ---------
|X| | |DIRN|XXXXX| | |
- --- -- ---- ----- ----- ---------
| | | | |
| | | | |
| | | | |
| | | | |_(2)Values of Direction (DEGREES)(6F10.0)
| | | |
| | | |_(1)Direction Number(I5)
| | |
| | |_Compulsory Data Record Keyword(A4)
| |
| |_Optional User Identifier(A2)
|
|_Compulsory END on last data record in data category(A3)(1) This is the number of the direction which corresponds to the values input in columns 21-30. This number must be one of the direction numbers specified in Data Category 6.
(2) The direction value should be the same as that specified in Data Category 6 and is used only as a check that the direction number (1) has been input correctly. It does not redefine the direction value. If the value is not the same, an error will occur.
Note: Effect of the DIRN Data Record when Running Aqwa-Line
Input of the Froude Krylov forces, diffraction forces or RAOs is redundant, when running Aqwa-Line, as the program normally calculates these parameters. The DIRN data record is a precursor to inputting values of these parameters. Therefore, use of a DIRN data record will instruct Aqwa-Line not to perform a radiation/diffraction analysis at this frequency. You must then specify all the other parameters which would otherwise have been calculated by the analysis at this frequency, i.e. the linear damping/added mass matrix, Froude Krylov and diffraction forces.