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

Wave pattern of ship is strange (VOF)

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 6, 2016, 15:15
Default Wave pattern of ship is strange (VOF)
  #1
New Member
 
Qingsong
Join Date: Mar 2016
Location: Netherlands
Posts: 10
Rep Power: 10
Qingsong is on a distinguished road
Hi, I'm Qingsong,

Recently I began to calculation ship resistance with free surface. In order to get quick response of my settings, I used less than 1 million nodes of mesh and inviscid flow. It may not generate accurate solution, but I think at least a physical solution. However, I got following strange wave pattern and velocity field.

So, if anybody encountered similar problem and know how to solve it, I will really appreciate that.


Solution 1:
Fluent 16.2, pressure based solver
Inviscid (ship model)
Boundary conditions:velocity-inlet (Fr=0.9) + outflow + ship(wall)+ far field(symmetry)
VOF + implicit
Methods: SIMPLE + Least square cell based + PRESTO! + Second Upwind + Compressive
already patch water region
initialize from air-inlet
Total flow time 1.939s
Mesh number: 0.77 million
Wave pattern and velocity field on free surface images are attached.
Problems:
1. Wave pattern is not physical solution, do you know why?
2. Velocity near inlet is not smooth


Solution 2:
Inviscid (ship model)
pressure-inlet (Fr=0.9) + pressure-outlet + ship(wall)+ far field(symmetry)
VOF + implicit + Open channel flow
Methods: SIMPLE + Least square cell based + PRESTO! + Second Upwind + Compressive
already patch water region
initialize from inlet
Flow time 21.288s
Mesh number: 0.27 million
Wave pattern and velocity field on free surface images are attached.
Problems:
1. Wave pattern is not physical solution.
2. Velocity near outlet is not smooth is higher than other place. This shouldn't be like this.


At the same time, if you are also working on such topic, welcome to discuss together.

Thank you in advance.
Qingsong
Attached Images
File Type: jpg Solution1-Wave pattern.jpg (22.4 KB, 40 views)
File Type: jpg Solution1-velocity field.jpg (19.5 KB, 34 views)
File Type: jpg Solution2-Wave pattern.jpg (17.2 KB, 30 views)
File Type: jpg Solution2-velocity field.jpg (20.3 KB, 32 views)
Qingsong is offline   Reply With Quote

Old   April 25, 2016, 12:49
Default
  #2
New Member
 
Qingsong
Join Date: Mar 2016
Location: Netherlands
Posts: 10
Rep Power: 10
Qingsong is on a distinguished road
After refinement of mesh on free surface, problem seems been solved.
Qingsong is offline   Reply With Quote

Reply

Tags
fluent, ship, vof, wave pattern


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
VOF wave getting damped. arun7328 STAR-CCM+ 16 July 8, 2019 16:06
Refinement for VOF wave arun7328 Siemens 4 January 21, 2019 09:57
wave pattern problem running LTSInterFoam Alex song OpenFOAM Running, Solving & CFD 2 May 10, 2015 04:14
vof method of wave height gtfeng STAR-CCM+ 2 June 8, 2013 03:32
HELP! UDF sinusoidal wave, VOF model, porous face! A8anato_psofimi FLUENT 2 November 10, 2009 15:42


All times are GMT -4. The time now is 15:41.