DTCHull (centre of gravity)

guzman · October 12, 2015, 10:45

I am trying to run DTCHull case with version 2.4.0.

I am trying to run the analysis for a different vessel and I need to know how to implement the centre of gravity of the ship.

In the DTCHull case (dynamicMeshDict) the following data appears:

centreOfMass (2.929541 0 0.2)

This appears to be the position of the centre of gravity of the vessel w.r.t the global coordinate system, i.e. the system of the block mesh of the water and air. Looking at the coordinates of the vessel (the hull), these appear to be defined in a coordinate system located at the bottom-left corner of this vessel.
Therefore, I would expect to find a vector defined between the vessel to define the coordinates of the vessel and the centre of gravity of the vessel. However, I cannot find this in any of the input files used in this example.
Can anyone explain if the reasoning above is correct and if yes, where this vector is defined?

Many thanks in advance

Zyryx · November 13, 2015, 07:17

You don't need any additional vectors, origin of the vessel is also the origin of the entire domain.

Sachin m · October 4, 2020, 13:35

I have the same doubt.
Any body figured out this.
Any body have any explanation for the dynamicmeshdict?

Sachin m · April 21, 2021, 02:28

Quote:

Originally Posted by guzman

I am trying to run DTCHull case with version 2.4.0.

I am trying to run the analysis for a different vessel and I need to know how to implement the centre of gravity of the ship.

In the DTCHull case (dynamicMeshDict) the following data appears:

centreOfMass (2.929541 0 0.2)

This appears to be the position of the centre of gravity of the vessel w.r.t the global coordinate system, i.e. the system of the block mesh of the water and air. Looking at the coordinates of the vessel (the hull), these appear to be defined in a coordinate system located at the bottom-left corner of this vessel.
Therefore, I would expect to find a vector defined between the vessel to define the coordinates of the vessel and the centre of gravity of the vessel. However, I cannot find this in any of the input files used in this example.
Can anyone explain if the reasoning above is correct and if yes, where this vector is defined?

Many thanks in advance

Have you found solution for this?

October 12, 2015, 10:45	DTCHull (centre of gravity)	#1
guzman New Member guzman Join Date: Sep 2015 Posts: 6 Rep Power: 10	I am trying to run DTCHull case with version 2.4.0. I am trying to run the analysis for a different vessel and I need to know how to implement the centre of gravity of the ship. In the DTCHull case (dynamicMeshDict) the following data appears: centreOfMass (2.929541 0 0.2) This appears to be the position of the centre of gravity of the vessel w.r.t the global coordinate system, i.e. the system of the block mesh of the water and air. Looking at the coordinates of the vessel (the hull), these appear to be defined in a coordinate system located at the bottom-left corner of this vessel. Therefore, I would expect to find a vector defined between the vessel to define the coordinates of the vessel and the centre of gravity of the vessel. However, I cannot find this in any of the input files used in this example. Can anyone explain if the reasoning above is correct and if yes, where this vector is defined? Many thanks in advance

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
simpleFoam with gravity, based on interFoam	JonW	OpenFOAM	1	May 9, 2019 10:08
Convergence problem when use gravity	aroma	STAR-CCM+	1	April 10, 2013 10:18
rigid body rotation through an axis not passing through centre of gravity	ranjith	CFX	5	November 22, 2012 16:08
Ok to increase gravity gradually from 0 to 9.82?	Admo	FLUENT	3	February 23, 2012 10:43
On gravity modelling...	Drona	CFX	7	November 22, 2001 10:28

November 13, 2015, 07:17		#2
Zyryx New Member Sebastian Join Date: Nov 2011 Location: Poland, Gdynia Posts: 5 Rep Power: 14	You don't need any additional vectors, origin of the vessel is also the origin of the entire domain.

October 4, 2020, 13:35		#3
Sachin m Member Sachin Join Date: Aug 2014 Location: India Posts: 84 Rep Power: 11	I have the same doubt. Any body figured out this. Any body have any explanation for the dynamicmeshdict?