Simulate a vessel sailing in a numerical tank

wangmw

I want to simulate a vessel sailing in a numerical tank with fixed draft and uniform rectilinear motion along the X-axis. So it has two constraints. The first is fixed Z-coordinate of gravity center, the second is X-axis velocity. Does anyone know how to define the first constraint? Thanks.

Alex

you can define different movements or variable gravity
check the guide and MOTION directory for that

if you still have problems, email to us (dualsphysics@gmail.com)

wangmw

Z-coordinate of gravity center does not change if the vessel is not treated as floating object and only X-axis velocity is allowed. Am I right?

By the way, I studied the test case CASEFORCES under RUN_DIRECTORY. Varying gravity is specified in varAccInputFile_0.csv and varAccInputFile_1.csv. Is the file name varAccInputFile_{n} mandatory?

Alex

"Z-coordinate of gravity center does not change if the vessel is not treated as floating object and only X-axis velocity is allowed. Am I right?" OnlyX-axis velocity is allowed???? I am not sure what you are talking about???

"Is the file name varAccInputFile_{n} mandatory?" OBVIOUSLY NOT

wangmw

The scenario is the vessel sails in the tank along the longitudinal axis at a fixed speed. In the test case, the vessel is not treated as floating object and a rectilinear motion in the X-direction is specified. Besides, I want to restrict the movement in the Y-direction. That's all.

Another question. If the file name is mandatory, where and how to specify it?

Alex

Please check the input XML file of CASEFORCES and you will find the answers to your questions about the file name.

In order to restrict the movement of the vessel, I guess the best option is to predefined the movement and load it from an external file or define it as floating object with an external force and restrict the degrees of freedom you want on the source files.

Regards

wangmw

Yes. I found the file name in the input XML file of CASEFORCES.

I guess external forces cannot be applied to floating objects. Because floating objects are not treated as fluid particles. Please refer to "Possibility of adding external forces" section in the user guide.

Maybe the best option is to predefine the movements from external files. I checked Motion08.xml and Motion01.xml. I don't quite understand the meaning of some keywords, such as "start", "finish", "duration". It seems the "finish" value does not equal to the sum of all "duration" values.

And what is the measurement unit of velocity? dp or actual coordinate?