target cell size for the internal free surface

laurent98 · April 23, 2012, 19:30

dear all,
i am trying to mesh a boat 20m long, in a 100*40*30 meters box, with Hexpress.
what can be the maximum target cell size to get a simulation of waves and boat drag not to bad...
with X=1 y=1 z=0.01 and a aspect ratio of 100 i get 4 000 000 cells
thank you for reply
LL

Rombzh · April 24, 2012, 18:37

The usual guideline is to have a normal resolution of Lpp/500 or Lpp/1000, and to reach that kind of resolution with a level of refinement of 7 or 8. So basically your initial mesh size in the Z direction would be (Lpp/500)*2^7.

When it comes to waves, 80 points per wave length, and 10 points per wave height.

PeiSan · August 6, 2014, 05:48

Hi,

I actually dont know how to find the target cell number since inside tutorial got teach but i already try use the formula that available in manual. However still cant get it. Is it i wrongly use the formula? Then i use the formula you write out, the value given out is so small. My Lpp is 1.372m

April 23, 2012, 19:30	target cell size for the internal free surface	#1
laurent98 Member laurentL Join Date: Oct 2011 Location: new caledonia Posts: 73 Rep Power: 14	dear all, i am trying to mesh a boat 20m long, in a 1004030 meters box, with Hexpress. what can be the maximum target cell size to get a simulation of waves and boat drag not to bad... with X=1 y=1 z=0.01 and a aspect ratio of 100 i get 4 000 000 cells thank you for reply LL

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Building OpenFOAM1.7.0 from source	ata	OpenFOAM Installation	46	March 6, 2022 13:21
[snappyHexMesh] Number of cells in mesh don't match with size of cellLevel	colinB	OpenFOAM Meshing & Mesh Conversion	14	December 12, 2018 08:07
How to define size of domain for free surface simulation?	Sunya	Main CFD Forum	2	June 8, 2009 23:33
fluent add additional zones for the mesh file	SSL	FLUENT	2	January 26, 2008 11:55
CFX4.3 -build analysis form	Chie Min	CFX	5	July 12, 2001 23:19

April 24, 2012, 18:37		#2
Rombzh Member Romain Join Date: May 2009 Posts: 40 Rep Power: 16	The usual guideline is to have a normal resolution of Lpp/500 or Lpp/1000, and to reach that kind of resolution with a level of refinement of 7 or 8. So basically your initial mesh size in the Z direction would be (Lpp/500)*2^7. When it comes to waves, 80 points per wave length, and 10 points per wave height.

August 6, 2014, 05:48		#3
PeiSan New Member Lim Pei San Join Date: Mar 2014 Posts: 25 Rep Power: 12	Hi, I actually dont know how to find the target cell number since inside tutorial got teach but i already try use the formula that available in manual. However still cant get it. Is it i wrongly use the formula? Then i use the formula you write out, the value given out is so small. My Lpp is 1.372m