UWAVE and UEXTERNALDB

This is a multipurpose verification problem for stochastic wave analysis with user subroutine UWAVE. The first of the four objectives is to test the restart capability; accordingly, the job is set up to rerun the dynamic analysis (Step 2) in uwavexx2.inp. The second objective is to exercise the coding for stochastic wave analysis, which is invoked with gravity waves using user subroutine UWAVE. A random number seed and the wave spectrum (wave frequency/amplitude data pairs) can be specified. These data are optional; dummy values for the random number seed and the wave spectrum are specified here to verify that they are accessed correctly in subroutine UWAVE during the analysis.

For stochastic wave analysis an intermediate configuration is available to UWAVE. This intermediate configuration can be used to store a user-chosen configuration upon which the wave kinematics are based. The third objective of this problem is to exercise the coding that performs the updating of the intermediate configuration. To this end, the UWAVE routine specifies that for the dynamic analysis (Step 2) a global update be performed for all elements at increments 1 and 141; and a local update be performed for a single element at 10-increment intervals, starting at increment 11 for element 1 and finishing at increment 101 for element 10. The local updates are requested sequentially for elements 1 through 10. For each global and local update request, the code updates the intermediate configuration with the current configuration for all the elements in the model and for the individual element, respectively. In this second step the updated intermediate configuration is stored in a common block array for manipulation in Step 3.

Step 3 is a dummy step used to overwrite the NFORC records with intermediate configuration information. When UWAVE is executed for this step, the intermediate configuration data stored in the common block are saved to an external file (UWAVEXX3.017) for subsequent postprocessing. To facilitate internal QA of the intermediate configuration data, the program UWAVEXX5.f is run to transfer the data from UWAVEXX3.017 to UWAVEXX3.fil by overwriting the dummy NFORC records created in Step 2. The resulting file, UWAVEXX3.fin, is then renamed to UWAVEXX4.fil to allow for data manipulation via accessing the NFORC records.

The last objective is to test the UEXTERNALDB user subroutine interface. This subroutine can be used to manage user-defined external databases. When this subroutine is called at the beginning of the analysis, it allows for opening external user files and initialization of external user common blocks. When this subroutine is called at the end of the analysis, it allows for closing open external files. In this example the UEXTERNALDB subroutine creates, opens, and writes to the file UWAVEXX3.96 using Fortran unit 96. The dummy wave spectrum data are written to this file.