boundcorrection of v4.3
A question about the new function of boundcorrection of v4.3:
Is the gap between the fluid and the particles was corrected in the boundcorrection of 4.3?
Is the gap between the fluid and the particles was corrected in the boundcorrection of 4.3?
Comments
The boundcorrection is still under development.
And beta version 4.3 only includes that correction for fixed and moving boundaries with simple geometries, but no for floating rigid objects.
We will extend and improve this correction for v4.4
Regards
thanks to you
I have a question about the floating . In the xml I use drawmode=full to generate sphere So the sphere is full of granules. And I use drawmode=full to generate a poly (stl) but the poly is empty and only the boundary are granules. So will it have some effection to accurancy calculation？
In order to fill your geometry with particule you should use fillbox (see XML_v4.0_GUIDE.pdf page 44)
Basically, you specify a seed, a reference point and a size of box. Then the program wil instantiate particule from the seed inside the box while the modfill is true (in your case I'd put void)
bye
You mean if I use stl to generate floating, the floating must be filled with particles or the result may be wrong?
the interaction between fluid and floating is different from boundary?
Is it relate to the relativeweight.do you think so?
Regards
These days I read the JSphBoundCorr.h and JSphBoundCorr.cpp. But I am confused with these variables:
//-Configuration parameters.
TpDirection AutoDir; ///<Direction configuration for automatic definition.
double AutoDpFactor; ///<Point is calculated starting from bound particles at distance dp*AutoDpFactor.
tdouble3 LimitPos; ///<Limit between boundary and fluid.
tdouble3 Direction; ///<Direction to fluid particles.
tfloat4 Plane; ///<Plane in limit.
Although there are explanition after the definitons.
Is AutoDpFactor to remove the gap between fluid and boudnary?
What is the role of limit between boundary and fluid?
Is there any papers about the metheod of boundary correctiong recommended ?
All regards.
We are now improving and testing the algorithms and then we will produce some journal papers.
We will let you know when we have more improvements.
Regards
The boundarycorrection can just be used on CPU calculation， and could not be used on GPU now, right?
About the boundary correction I see 8 directions in the JSphBoundCorr.h,top/bottom/front/back/left/right/none/defined. So I want to know if the correction can be applied to the complex boundary, like a stl boundary(fixed boundary)?
"Dear user
The boundcorrection is still under development.
And beta version 4.3 only includes that correction for fixed and moving boundaries with simple geometries, but no for floating rigid objects.
We will extend and improve this correction for v4.4
Regards"
Regards
Your sound of speed should be 10 times higher than the highest velocity in your simulation. Ie. if the highest velocity in your simulation is 1, set it to 12 (just to be safe) - don't use the physical correct value of your fluid since the only purpose of sound of speed is to ensure incompressibility according to Tait's equation.
I hope it helped a bit.
Kind regards
You should also pay attention to the use of:
Also seems like some of your comment is missing, I can't see anything after "You should also pay attention to the use of:"?
Kind regards
parameter key="DtAllParticles" value="0" comment="Velocity of particles used to calculate DT. 1:All, 0:Only fluid/floating (default=0)"
Thanks for your reply, and I am trying some testcase considering your idea.
Today I run a example of floating in /examples/main/12_Floatingwaves/CaseFloatingWaves_Def.xml
There is a floating box with density 680kg/m3 . I change the initial positon of the box
case 1: the initial position is above water and got the result as follows
case2: the initial position is below freesurface and in the water and got the result as follows
In case1 the gap between fluid and floating is obvious but in case 2 the gap is not obvious.
So why is the result different?
It's because particles are created in a cartesien grid
so if you create your floating in water there is going to be particles directly next to it.
However, this is not a solution. if your floating goes out of water then the gap will properly form.
You can observe this by putting a moving part under your floating and liftthe floating out of water and then in again
The same effect can be seen in boundaries also. if you look at example dam break you'll see water having no gap in the inital area and then having the gap in other locations
@TPouzol
@Asalih3d
About the correction of boundary . I see the clarification of Dynamic Boundary Conditions in Guide.pdf.
That means when the floating interacts with the fluid and the distance between fluid particles and boundary particles are less than 2 times smoothing length, the density of the boundary particles increases , resulting in an increase in pressure, thereby creating an interaction between the fluid and the floatings.
In version 4.3, what is the modification of the boundary of the fixed boundary, what is the basis for the correction, and how is the interaction between the fluid particles and the boundary particles? What is the difference with Dynamic Boundary Conditions?
Could you make some explaination? Thanks a lot
regards
Only v4.3 include some preliminary stuff, but that was a BETA version for delegates of the 4th DualSPHysics User Workshop. However since it is only BETA and this work is now under development we can not release that and there is no proper documentation... So there is no sense to explain now what we are working on....
I am sorry
Regards