Trim optimization

Hi aupetit24250,

If the Domhydro tool is already not able to compute the parameters, there might be some issues with your domain (geometry). Did your mesh generate correctly and did the computation run as expected? Could you check whether the body is defined correctly in the Body definition menu? If Domhydro failed to calculate the parameters, it will also not have set the correct mass, CoG and inertia matrix values, so I doubt the computation has run correctly. 

In order to help you out, it would be really useful to also have a look at the cwizard.log file in the project folder, as well as the domhydro.out file in the _mesh folder. You might also want to verify that you're not using nonstandard characters in the project name and check the documentation3

Kind regards, 

Maurits
Marine CFD Product Engineer 

Thank you for this response but on the different files I haven't seen problems.

I explain the purpose of my study because I may not be using the right method. My objective is to simulate the movement of a kayak at a given speed and by varying the position of the centre of gravity at each simulation in order to find the best positioning of this one bringing us the weakest drag. Once the best position of the centre of gravity is found, I want to find the position of the water line in dynamic and static. My problem is to find the position of the water line in static because I can't find how to do it. I thought that by knowing the dynamic trim, I could find the static water line by making an angular shift (of the dynamic trim value) of the dynamic water line. Do you know how I could get the static waterline in a simple way, maybe there is a module on the software?

Thank you for this response but on the different files I haven't seen problems.

I explain the purpose of my study because I may not be using the right method. My objective is to simulate the movement of a kayak at a given speed and by varying the position of the centre of gravity at each simulation in order to find the best positioning of this one bringing us the weakest drag. Once the best position of the centre of gravity is found, I want to find the position of the water line in dynamic and static. My problem is to find the position of the water line in static because I can't find how to do it. I thought that by knowing the dynamic trim, I could find the static water line by making an angular shift (of the dynamic trim value) of the dynamic water line. Do you know how I could get the static waterline in a simple way, maybe there is a module on the software?

Thanks for the explanation. 

You can obtain the static equilibrium by using domhydro, assuming that you are correctly labeling the patches (all patches belonging to a body ending on _b#, where # is the number of the body). If you check the documentation on the tool, it should become quite clear how to obtain the hydrostatic parameters. The static waterline depends on the center of gravity and the immersion of the body. In order to find the optimum location of the CoG to obtain the lowest drag, you will have to run computations with different CoG positions and static waterlines. You can use the p2h mode (parameters to hydrostatics) of Domhydro to obtain the hydrostatic position if you know mass and CoG as explained here.

Kind regards, 

Maurits

Thank you for your reply, that's what I was thinking of doing but my problem still persists. You can watch the photos of my settings entered in c-wizard. I may be making a mistake in the settings. When meshing, I use the merge tool to group all the surfaces of the body into one. You can also see that there is a _b# at the end. On the pictures you can also see the errors displayed. Thanks for your help.

Let me know if you have a problem viewing the images or if you need more information.

Thank you a lot.