CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > CFX

Solid object falling in water tank simulation

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree1Likes
  • 1 Post By ghorrocks

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 11, 2014, 19:00
Question Solid object falling in water tank simulation
  #1
New Member
 
Alberto
Join Date: Jun 2014
Posts: 2
Rep Power: 0
cassini83 is on a distinguished road
Hello fellow CFD experts,
I need your help setting up this simulation in CFX. From the physical standpoint, the scenario is somewhat straight forward. The scenario goes as follows:
A stationary tank with water (like a glass of water) is subject to a solid object moving through (translation domain for the solid) from the top surface of the water to the bottom of the tank. After the solid is pushed to the bottom of the tank, it is left to interact with the fluid (and assuming its density is less than the liquid) one shall see the solid float to the surface.
The goal of the simulation is to visualize the transient fluid velocity profiles created as a result of the moving object. Ideally, I would like to estimate how long it takes for the water to get back to zero velocity (equilibrium) after one cycle (pushing the solid to the bottom of the tank and letting go of it and reach the surface).
This is obviously a transient simulation, with several domains (stationary and moving). Also, buoyancy would have to be enabled.
Any suggestions as to how to approach this setup would be greatly appreciated. After the simulation is setup, the ultimate goal is to optimize the shape of the solid object in order to "maximize" the time it takes for the water to get back to zero velocity.
Thanks!

Last edited by cassini83; June 11, 2014 at 22:18.
cassini83 is offline   Reply With Quote

Old   August 7, 2021, 21:44
Default Modelling A solid particle dropping into a Tank
  #2
New Member
 
Arnold
Join Date: Aug 2021
Posts: 2
Rep Power: 0
aspsarv is on a distinguished road
Hi every one,

I would like also to let me know about how to model a solid object dropping into a Tank.

Thanks
Arnold.
aspsarv is offline   Reply With Quote

Old   August 8, 2021, 18:06
Default
  #3
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,144
Rep Power: 134
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
If you model this in a stationary reference frame then the water is stationary and the body moves relative to it. This can be done using immersed solids or a rigid body solver. But this is a hard way of doing it as you will need a very large and fine mesh.

The easiest way of doing it is to model the body in a frame of reference fixed on the body. Then do a series of simulations with the fluid moving over the body at different velocities. This gives you a drag versus speed curve, and you can use a simple ODE (ordinary differential equation) solver to then predict what this drag versus speed curve makes the body motion.

The easy way of doing it will work as long as you don't have complex motion (eg the body zig-zags or spirals as it moves) or the transients at start up or stopping are not important.
aero_head likes this.
__________________
Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.
ghorrocks is offline   Reply With Quote

Old   August 9, 2021, 17:05
Default
  #4
Senior Member
 
Gert-Jan
Join Date: Oct 2012
Location: Europe
Posts: 1,533
Rep Power: 23
Gert-Jan will become famous soon enough
I would opt for Overset Meshing in Fluent, which is more accurate than immersed solids in CFX.
Gert-Jan is offline   Reply With Quote

Reply

Tags
buoyancy, tank

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
simulation of free falling sphere into calm water? pedyspider CFX 17 June 25, 2015 11:03
Falling Water Droplet Simulation Joe101 ANSYS 1 June 23, 2014 16:54
Water subcooled boiling Attesz CFX 7 January 5, 2013 03:32
Free water jet impinging hot solid surface, including boiling hamdy Fluent UDF and Scheme Programming 5 August 19, 2012 19:52
Terrible Mistake In Fluid Dynamics History Abhi Main CFD Forum 12 July 8, 2002 09:11


All times are GMT -4. The time now is 00:39.