Boat simulation; issues with active body

[JuhaHo]

Has there been any changes in active bodies feature? I gave up earlier, because I didn't get expected results with planing hull boats. I could not achieve the real world position and angle,

[Svetlin.Nikolov]

Hey JuhaHo , check the active body chapters in this video https://forums.chaos.com/forum/phoen...overview-video

This might give you some ideas what to try.

[waaazoo]

Hey, just wanted to confirm - are you changing the center of mass on tbe original or on the clone?

Btw, we are thinking about just using the pivot of the geometry for this...

Hi Svetlin,

I tried nearly everything I tried changing the location of CenterOfMass of the original, of the clone. I tried to change the pivots of the mesh (original and clone). BTW, simulator grid is not moving.
First simulations tests were working, but I had a locked Y translation (my mistake). Now that I unlocked this Y translation, the boat rotates on it's axis like #4 page01.
I will read again this full topic to see if I missed any hint.

[JuhaHo]

Here's my latest comparison between Phoenix 4 and 5.

On both simulations, the problem is almost non existent side wake as well as very low amount of foam on the sides of the boat. That doesn't reflect the real life behavior of this boat hull. On the photos, there's very high wake on the bow. What should I do to see it on simulation as well?

[waaazoo]

Here's my latest comparison between Phoenix 4 and 5.

On both simulations, the problem is almost non existent side wake as well as very low amount of foam on the sides of the boat. That doesn't reflect the real life behavior of this boat hull. On the photos, there's very high wake on the bow. What should I do to see it on simulation as well?

Hi,

Yes, your hull seems to have very low impact onto the liquid. Is your boat enough deep into the water ? What's the official waterline? Also, do you work in real world units ?

[JuhaHo]

Hi,

Yes, your hull seems to have very low impact onto the liquid. Is your boat enough deep into the water ? What's the official waterline? Also, do you work in real world units ?

Thanks,

I got complaints from the hull designer, that the boat is already too deep in the water. I extended the keel height and width hoping it would penetrate deeper in the water. Now I'm thinking to create some kind of a bulge, that would throw the water sideways and also generate more foam.

[waaazoo]

hmm, how strange. Your boat looks like it is already flying. Do you have "clear inside" activated ?

[JuhaHo]

hmm, how strange. Your boat looks like it is already flying. Do you have "clear inside" activated ?

Yes, it's activated and the hull model is watertight. The speed is more than 50 kn. I see time to time these boats when I'm on my own boat trips on nearby sea. They really have huge foam rising on the sides.

[waaazoo]

maybe you can try to change the "motion velocity effect" of the hull's Phoenix attributes.

[JuhaHo]

maybe you can try to change the "motion velocity effect" of the hull's Phoenix attributes.

Thanks,

I started two simulations: one with value 2.0 (instead of the default 1.0) and the other with value 4.0. The latter is running on Phoenix 5. I'll let you know what happens. It will take a day or two.

[waaazoo]

Svetlin.Nikolov Is the boat active body setup supposed to work with wave force ? So far, my makes the boat hull to freak out

[georgi.zhekov]

Should be working, yes. Can you show us how it looks?

[waaazoo]

Should be working, yes. Can you show us how it looks?

Well, I'm not allowed to show the hull. My setup, procedure was the following:

1- setup a static grid. First test with no initial velocity and no magnitude (on thruster). Also no WaveForce to be sure that my hull is floating correctly -> this went well

2- setup a value for initial velocity and magnitude (Thruster) to match a given speed with a reference boat. Still no Waveforce. -> boat hull is moving, produces liquid wake and I was able to reproduce a similar speed.

3- use of this setup but added the waveforce. I tried with massive waveforce and without. waveforce is animated to start only at frame 20 and having max strength at frame 50. The idea was to obtain "simple" waves around 1m height (see screen capture). -> first frames go well, but then the hull starts to rotate (bow up) and sink and so on.

In my different tests, the hull either pitches-up (nose up) sometimes very heavily, and then dives, but never has a "natural" movement. I was working/testing with SPF4.

[waaazoo]

same sim continued

[waaazoo]

Overall, it's quite difficult to find the right balance between magnitude/initial speed/hull density. And I'm still wondering if there are some other important settings to have control over speed, buoyancy and interaction with the liquid.