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user_manual_tomawac [2013/06/06 09:33]
j.parisi
user_manual_tomawac [2014/10/10 15:01] (current)
Line 2764: Line 2764:
 Since the boundary spectrum computation procedures are similar to those for the initial spectrum, refer to Since the boundary spectrum computation procedures are similar to those for the initial spectrum, refer to
 section 8.4 for further details. section 8.4 for further details.
 +
 +=== 8.5.3. The LIMWAC user subroutine ===
 +
 +It should be reminded that the spectrum is discretised over both frequencies and directions and that it is a
 +relative spectrum, i.e. expressed in a coordinate system that moves with the current.
 +
 +The subroutine LIMWAC, in its original version, allows to impose the spectrum components at each point of
 +a boundary with a prescribed value. The spectrum components are calculated from the parameters specified
 +in the CAS file (see section 7.2.1). This subroutine, however, can easily be modified to specify e.g. nonhomogeneous
 +(in space) boundary conditions. When such specific boundary conditions are required, these
 +will ideally be incorporated in the user part provided in the code of the LIMWAC procedure. The keyword
 +BOUNDARY SPECTRUM MODIFIED BY USER must also be set to YES.
 +
 +==== 8.6. Some useful subroutines ====
 +\\
 +
 +=== 8.6.1. Modification of bottom topography: CORFON subroutine ===
 +
 +The seabed levels can be modified in two different ways, as already stated in section 7.5.
 +
 +The seabed levels can be modifed at the beginning of the computation using the CORFON subroutine, which
 +is called once at the beginning of the computation. This subroutine allows the value of the ZF variable to be
 +modified at each mesh point. For this purpose, a number of variables such as, for instance, the point
 +coordinates,​ the element area values, the connectivity table, etc., are provided.
 +
 +By default, the CORFON subroutine performs the same number of bottom smoothing iterations as LISFON,
 +i.e. the same value as specified by the integer keyword BOTTOM SMOOTHINGS.
 +
 +Note that the CORFON subroutine is not called in case the computation is initialized with the result of a
 +former TOMAWAC run (“hot start”).
 +
 +This subroutine is part of the TELEMAC-2D library and is listed in APPENDIX 2.
 +
 +=== 8.6.2. Modifying the co-ordinates:​ CORRXY subroutine ===
 +
 +TOMAWAC allows the mesh point co-ordinates to be modified at the beginning of the computation,​ so that
 +an up-scaling (switching from a small scale model to a full-size model), a rotation or a translation can be
 +performed.
 +
 +Such changes are made using the CORRXY subroutine from the BIEF library, which is called in at the
 +beginning of the computation. This subroutine is void by default and provides, in the form of a comment, an example of programming relevant to a change of scale and origin. It is part of the TELEMAC-2D library and
 +is listed in APPENDIX 2.
 +
 +=== 8.6.3. Operations on vectors: OV subroutine ===
 +
 +The BIEF library has a range of very useful subroutines including, in particular, subroutines for operations on
 +vectors. A number of relations have been programmed so that loops can be replaced by a mere procedure
 +call.
 +
 +The syntax is as follows:
 +
 +CALL OV(OP, X, Y, Z, C, NPOIN)
 +
 +Where OP is a string of exactly 8 digits that is indicative of the operation about to be performed on the X, Y,
 +Z vectors and the constant C. The result is the vector X.
 +
 +Example:
 +
 +  : CALL OV('​X=X+Y ', X, Y, Z, C, NPOIN)
 +  : Y is added to X, the result will be stored in X.
 +
 +A full list of available operations are given in the Guide to programming in the Telemac system version 6.0.