[Deepankar]

Hi,
I am working on Numerical Analysis of rigid body impinging in water using Ansys Fluent in which I have to calculate penetration depth of that body in the water. I am unable to do that kindly help me regarding that.
Thanks & Regards!

[CFDKareem]

Originally Posted by Deepankar

Hi,
I am working on Numerical Analysis of rigid body impinging in water using Ansys Fluent in which I have to calculate penetration depth of that body in the water. I am unable to do that kindly help me regarding that.
Thanks & Regards!

I'm going to assume the body is traveling down along the Z axis, but you can change it for whatever axis it is moving along.

You can plot a report definition for the minimum Z value of body. This will create a plot of the bottom edge of the body over time. If you know the level of the water then you can calculate how far the body penetrates. I would recommend drafting your domain with the water level at 0. Then, from you plot, the minimum value it achieves will be the penetration depth.

[Deepankar]

Originally Posted by CFDKareem

I'm going to assume the body is traveling down along the Z axis, but you can change it for whatever axis it is moving along.

You can plot a report definition for the minimum Z value of body. This will create a plot of the bottom edge of the body over time. If you know the level of the water then you can calculate how far the body penetrates. I would recommend drafting your domain with the water level at 0. Then, from you plot, the minimum value it achieves will be the penetration depth.

Thank you sir for this but if you can tell how to plot minimum Z value of body and how to predict the penetration depth by knowing water depth. I am still unable to do, I have to show the plot of penetration depth w.r.t. time. My domain is 1.5*1.5*7m and water depth I took is 2m and a cylinder with hemispherical head of radius 0.2m and length 0.6m is dropped from air(free fall) from a height of 3m.
Can you please tell me from scratch or if possible please make a video on this?

[CFDKareem]

Originally Posted by Deepankar

Thank you sir for this but if you can tell how to plot minimum Z value of body and how to predict the penetration depth by knowing water depth. I am still unable to do, I have to show the plot of penetration depth w.r.t. time. My domain is 1.5*1.5*7m and water depth I took is 2m and a cylinder with hemispherical head of radius 0.2m and length 0.6m is dropped from air(free fall) from a height of 3m.
Can you please tell me from scratch or if possible please make a video on this?

I would love to make a video on this. It will be much easier to explain.

Could you provide some images of your domain as well as the boundary conditions such as the size and speed of the sphere?

[Deepankar]

Originally Posted by CFDKareem

I would love to make a video on this. It will be much easier to explain.

Could you provide some images of your domain and the boundary conditions, such as the size and speed of the sphere?

The body I took is a cylinder with a hemispherical head of radius 0.2m and length 0.6m dropped from the air(free fall) from a height of 3m. The water depth is 2m, and the domain size is 1.5*1.5*7m. I just took the boundary condition as the fluent took automatically means all the walls of the domain are wall boundary conditions. I took the top wall of the domain as the specified pressure boundary where I have given a pressure inlet.
I used a dynamic mesh where I took only The body as the component zone and considered it as a rigid body only, mapped it with the mass of the object 19kg and took One degree of translation, and put the "y" value as 1. And did the hybrid initialization and patched it. I have taken two phases 1st is air and second is water.

[Deepankar]

Originally Posted by Deepankar

The body I took is a cylinder with a hemispherical head of radius 0.2m and length 0.6m dropped from the air(free fall) from a height of 3m. The water depth is 2m, and the domain size is 1.5*1.5*7m. I just took the boundary condition as the fluent took automatically means all the walls of the domain are wall boundary conditions. I took the top wall of the domain as the specified pressure boundary where I have given a pressure inlet.
I used a dynamic mesh where I took only The body as the component zone and considered it a rigid body, mapped it with the mass of the object 19kg and took One degree of translation, and put the "y" value as 1. And did the hybrid initialization and patched it. I have taken two phases 1st is air and second is water.

And also, one more problem is there, sir. When It hits the water surface, it doesn't create any splashes, and no water surface breaking is observable. What to do , where I am doing wrong? Kindly provide some solution.

[PacMan]

Originally Posted by Deepankar

And also, one more problem is there, sir. When It hits the water surface, it doesn't create any splashes, and no water surface breaking is observable. What to do , where I am doing wrong? Kindly provide some solution.

Are you using VOF? what are the boundary conditions on the moving object?

[Deepankar]

Originally Posted by PacMan

Are you using VOF? what are the boundary conditions on the moving object?

Yes, I am using VOF. And I am attaching screenshots of all the steps I took in the setup part numbered in sequence. Kindly look at that.
I have taken the body as a component zone and the domain as the background zone.
All the walls of the domain I took as walls-background except the upper wall.
For the upper face wall, I have taken the "specified pressure zone," which I gave as pressure inlet (Atmospheric pressure), as you can see in the screenshots.

[Deepankar]

Yes, I am using VOF. And I am attaching screenshots of all the steps I took in the setup part numbered in sequence. Kindly look at that.
I have taken the body as a component zone and the domain as the background zone.
All the walls of the domain I took as walls-background except the upper wall.
For the upper face wall, I have taken the "specified pressure zone," which I gave as pressure inlet (Atmospheric pressure), as you can see in the screenshots.