'Wind catching hull' simulation project by WaBe


#1

I created a new simulation project called 'Wind caching hull':

The goal is to see how the air flows around a hull and wing body when the hull is angled to windward


More of my public projects can be found here.


#2

Hello @WaBe,

I saw your comment in the “Introduce yourself” topic! Nice project that you are working on! That is why I quickly checked on your project. External aerodynamics of a wing geometry are of course possible on SimScale.

In your current setup there is an issue with the Mesh though. When you add a mesh operation for external aerodynamics (Wind tunnel) the bounding box defining the fluid domain is automatically adjusted to the size of the geometry model. Of course it makes sense to improve the automatic settings by increasing the bounding box size particularly in the flow direction and behind the wing as there are the highest gradients to be expected. In your case the bounding box is defined by (-1,-1,-1,1,1,1) which does not even include the wing. I attached a screenshot below with the box as defined by the default settings on the right and your current setup on the left.

Happy to help on additional steps if needed!

Best Alex


#3

Hi @afischer

Thank you for taking your time. Yes, I am kind of lost.
I can not set the mesh and the object at the same time. Therefore I did not realize that the model is not inside.
Sure, I touch any button possible but I was sure that the mesh size was set by automatics. As I know that the boat is more than 2m so setting 1m is not good as you showed.
Ones I got to use the program it will be easy to see the mistakes.
Right now I am trying to understand how all is meant. It will take time and any help is very appreciated:

  • When I do login then I get always one of previous projects from the public area but how to set to get my?
    When I find my project the window is empty. It was not like this from begin.
    This happens after I did update the file describing the boat from igs to stl.

  • As I wrote can not find the way to make the mesh box transparent and see the boat inside as you can.

  • Sure I do need to learn also how to make the results of simulation visible. So the best will be maybe to copy a another similar and ready project and replace the model? is that possible?

Thanks again
/Waldemar


#4

Hi Waldemar!

Could you provide us with a screenshot? That would be great in order to see what exactly you are looking at when dealing with the model (which also implies why you cannot see your boat).

You could copy another project and just replace the model but that is not the way you should set up the model. This is useful when investigating the same model with different boundary conditions or different model with same or different boundary conditions.

The workflow should look like this: Pre Processing \rightarrow Processing \rightarrow Post Processing

Without mentioning now that the workflow is an iterative process where you might go back to a certain point, optimize, post process and so on… In general there is no strict rule for that, just to be clear.

I have the same issue with the model not being visualized in the Dashboard. That might have something to do with the data format of your model but I am not sure (never had this before). Maybe @afischer has a solution to this.

Edit: Reuploading the model of you solved the issue the preview of your ship in the Dashboard. See if that also works for you and let us know :+1:

Best,

Jousef


#5

Hello Waldemar (@WaBe)!

thanks for explaining your issues in detail. I assume you are referring to the thumbnail of your project with “the window is empty”. I can see this. One quick hint. We always show the “latest” result in the thumbnail of a project e.g. if there is a simulation result we show an automatically created thumbnail of it. If there is not sim result, we show the mesh or the geometry respectively. For your simulation the thumbnail creation obviously did not work. You can see it in the slider below the viewer on the project info page: https://www.simscale.com/projects/WaBe/wind_caching_hull/ . That explains why you saw the model beforehand as you did not have a sim result at that point. Now it shows the empty thumbnail of the result. We will look into that!

For your first two points, could you share your operating system and browser version that you are using as the transparency should work for all supported browsers! Additionally when you log in you should be forwarded to your Dasbhoard. Hence, only seeing your own projects. If this is not the case could you quickly describe which workflow you use to log in e.g. the login button on the website? what do you click afterwards. You can also share a gif (via private message or email if you like) if you have a screencast software available!

Hope we can figure it out fast, so that you can focus on your application again!

Best Alex


#6

Hi Alex @afischer

I send some info to contact@simscale.com with info about my system and some screen shots as pdf.
As I did not get any answer from you I suppose that this is not the correct way to do it - is it right?

Best Waldemar


#7

Hello Waldemar (@WaBe),

there was a misunderstanding on our side, the mail is sent to our support and did not get forwarded. I am sorry for that.

Thanks a lot for your very detailed explanation. In general the login behavior that you are seeing is intended. The main points are, if you log in

  • from the website www.simscale.com you are forwarded after the authentication to your Dashboard seeing your latest projects and your latest activities, jobs etc.
  • from a different page e.g. the public project page, a single project overview page etc or you try to do something that requires login you will be forwarded back to this page after authentication (that means that you need to click again on e.g. the “Open in workbench”-arrow after the login, we will consider improving this by directly opening the project after the entering the login information)

Right now the search that you used in the projects overview is saved. There was some confusion about it, so there will be probably an update for this in the next release.

You can decrease the text size by using your mouse-wheel outside of the viewer area, which of course also has disadvantages. We are continuously working on cleaning up those panels though, which will at least reduces the need of a scrolling bar.

As you mentioned also that you expected the geometry, mesh and simulation settings to be displayed at once in the Navigator, I also wanted to hint you to our Vote for features! section in the forum. If you would add there a topic for merging the complete work flow into one single tab with one navigator tree, then other user can comment on their preferences and up-vote your feature request! That would be actually great.

In regards to your mesh, the problem is still that your “wind-tunnel” base mesh box did not even cover the boat part. I’ll share you my setup in a second.

Best Alex


#8

One additional note. If you are interested in the boat moving due to e.g. the water/wind velocity fields, a possible setup is to use a multiphase analysis involving so-called 6-DOF motion. There are quite some good examples on SimScale e.g. @Ali_Arafat’s and @sjoshi’s projects:

https://www.simscale.com/projects/Ali_Arafat/free_floating_boat_in_a_wave_tank/
https://www.simscale.com/projects/sjoshi/wake_development_behind_a_boat/

If you are only interested in the air flow around the “fixed” boat shape a standard incompressible simulation is sufficient.

Best Alex


#9

See the mesh containing the boat here. Please note this is a very coarse mesh, just a first try to check on the setup. The “plate/water surface” where the boat is placed on influences the mesh in this region. It would make sense to remove this from the model I guess.

https://www.simscale.com/projects/afischer/wind_catching_hull

Best alex


#10

Hi Alex @afischer

Nice to se the boat inside but I am waiting to learn how to get the same in my project ? Can you copy your project over my stuff? Or can you put is public so I can copy?

The Ctrl + mouse wheel works fine = progress…

The plate standing for water surface will be removed as you said.
The boat hull will be cut in its heeled water line and put on the floor - right?

The 6-DOF is very interesting possibility. Now I have a question in order to understand how far it will be possible to go.
Its is about own wind pressure due to movement.
So the question is following:

  • if the boat is virtually moving in the wind tunnel with speed 5m/s in -x direction and the wind tunnel air speed is 0m/s is the simulation result the same when the boat is not moving while the wind tunnel have air speed of 5m/s in x direction?

It is the same question: can we simulate a football having certain starting speed and rotation facing side wind? Can the trajectory be simulated?
Sorry for this demanding questions but I do not know where the technology is right now. And it will be fun to know!

And YES I would like to simulate more when its come to sailing boats with variable wings…

Best Waldemar


#11

Hey Waldemar,

yeah the project is already public, if you click on the link above the image you can simply copy again.

Using the air velocity instead of the object movement is the usual approach e.g. for cars, you apply the velocity as inlet on the air, you can add a moving wall for the ground and rotating wheels and simulate via this the actual behavior of the car moving and the ground and the air “standing still”.

For the 6-DOF applications it is always the crucial point if the relative movement is small or big in regards to the mesh domain/mesh fineness. See this validation case for example:
https://www.simscale.com/docs/content/validation/FreeHeaveMotion/FreeHeaveMotion.html

We also have public projects for the flow around football or golf balls but as far as I know none involving 6DOF.
https://www.simscale.com/projects/SamPrabhu/golfball03/

Best Alex


#12

Hej Alex @afischer

It was first what I did but do not like admit failure…
This link shows other your projects but the text inform:

"Sorry, that content is not here or has been removed.
Please double check that your link is not mistyped and complete."

One thing is that when I do activate the link in e-mail program then the browser called MS EDGE is starting which is not choose as standard browser by me.
EDGE is not approved by Simscale?
When I copy the url and paste into CHROME then the project we are talking about is still missing with text as copied above.

And thanks for the other links and explanations.

Best Waldemar


#13

Hello Waldemar,

sorry, my fault! The link should work now.

Best Alex