[rafa13]

Hi Mr.Jacobson and waves2foamers,

I am trying to simulate a porous Wave breaker and after successfully simulate a vertical wave breaker and a vertical porous wave breaker, I advanced to the next step; a porous wavebreaker with a certain steepness .But when I try this I qet problems at the interface of the porous and non-porous region. Right at the beginning of the simulation ( when the wave is generated ) I get some turbulences and strange particle movements at the interface face between the two regions, and this water displacement creates small waves in the opposite direction and the water fractions are being transported to the top of the wave breaker and through the air to the inlet.

I used the same configuration for the vertical porous wave breaker and for the inclined one and i am getting this strange behavior.
I dont know if it is a Meshing problem maybe I need to refine the zone at the interface when i introduce a steepness, or is there a conservation of mass problem?

someone experienced something like this and have some advices or ideas for this problem?

I'm using OpenFoam 2.2.2, and a Mesh with only rectangles and created with Gmsh

greeting everybody

Rafael Marques

[rafa13]

Hi everybody again,

I was thinking about this turbulence problems from the earlier post and I try to run the case with a refined mesh, but for now no results still calculating. But i am thinking about the relaxation zone maybe i did something wrong I eliminated the outlet relaxation zone is that the typical procedure ?

thanks

rafael marques

[rafa13]

Hi everybody

this image shows the problem that i explained in the previous post. Its clearly notable this water displacement at the porous zone interface but the wave is still in the relaxation zone, some one with an advice, I all ready refined the mesh, it get better but still there. I also try to change th discretization schemes but no change or is it normal for the first wave?





thanks to everybody

[rafa13]

Hi everybody,

i my last post i reported this strange water behavior, in my porous wave breaker simulation. I didn't post the imagem. And i still straggling with this issue , i tried several things but this strange water displacement at the porous media boundary is still there. I meshed the domain on several ways.
Somebody con help me with this problem, this picture shows the water displacement this imagem was took at the beginning of the simulation like 3s.
The relaxation zone have 10 meters and the distance from the inlet to the wave breaker is 37 meters. I am using a regular wave for the first study then my intention are to change the theories. I hope this is enough information.

thats the water displacement: http://imgur.com/ZJOKmxL

thanks and greetings

RM

[Olbap]

Hello Rafa,

Perhaps you could provide your entire case file? I'm new but I played around a bit with porous zones, and the information you provided is not enough for me to guess your problem...

Best,
Pablo

[rafa13]

Hi Pablo,

Thanks for the fast answer this link have all the information of the case, i hope you can see the mistake. Here is the link to the case:
https://www.dropbox.com/sh/c0dyw4nze...wiLjZGK-a?dl=0

One more information, I tried the same mesh but without porousmedia and this water displacements are still there, you can see it at this image:
http://imgur.com/DqHzI3T

thanks again

RM

[rafa13]

Hi everybody,

i solved the problem, by changing the mesh. My problem was that the mesh needs to be orthogonal in al the domain, so i made a mixed mesh with triangles in the porous zone and rectangular at the non porous zone and this strange water displacement disappeared the problem is that interfoam has a real problem with not orthogonal meshes.
By changing the mesh i reduced the max skewness to 0.48 and the aspect ratio to 4.8.

so i tried many things like changing the interpolation scheme to midPoint and the gradScheme to celllimeted but nothing works, the only recipe to achieve good results was to change the mesh in this photos everybody can see the changes.

1º mesh this one with the water displacement: http://imgur.com/S7nxgZr
2ºmesh, this one with the nice results: http://imgur.com/8n4BHnW

So now i understand that it is important to have a nice ortognal mesh to achieve nic results with porous media.

Greets to every body

Rafael Marques

[rafa13]

Hi Waves2Foamers,

In my last post, i made a better mesh for my study. Witch is a numerical simulation of the interaction of waves with a porous wave break.

I tried to better up the mesh even more, i 'am using gmsh and i am here only to show the last improve and to post the code which allows to create a orthogonal mesh on a triangle.
If some body are interested here comes,:


//Geometry of the triangle
//Input

lx=0.745;//lenght in X
ly=0.48;//lenght in X

n=12; // nr of horizontal points_ change to get a more refined grid

//nodes of the mesh
nosTH=11; //horizonta nodes (mesh between 2 nodes)_ change to get a more refined grid
nosTV=6; //verticais nodes (mesh between 2 nodes)_ change to get a more refined grid


//-------------------------------------------->Programm<--------------------------------------------------//

//Variables
a=0;
b=0;
l=n;
ii=1;
c=1;

//Triangle

//It counts the points of the triangle---k are the number of points
k=0;
For i In {1:n}
s=k;
k=s+i;
EndFor
s=1;
i=1;
a1=0;

//Creation of points
For i In {1:n}

pa=1;


For p In {ii:l}

a=a1+(pa-1)*ly/(n-1);
Point(p)={b,a,0};

pa=pa+1;

EndFor

c=c+1;
ii=p;
l=n+p-c;
s=s+1;
b=(s-1)*lx/(n-1);
a1=a1+ly/(n-1);

EndFor


//Vertical lines
l=n-1;
ii=1;
c=1;
pa=1;
s=1;
For i In{1:n-1}

For p In{ii:l}
Line(p)={pa,pa+1};
Transfinite Line {p}=nosTV;
pa=pa+1;
EndFor
c=c+1;
s=s+1;
pa=pa+1;
ii=p;
l=l+n-s;

EndFor

//Lines Horizontl/Obliqous/LineLoop & transfinite line

b=n;
s=1;
a=2;
ll=1;
For i In{1:n-1}


Line(p)={a-1,b+1};

If (i < n-1)
Line(p+1)={a,b+1};
Transfinite Line {p+1}=nosTH;
EndIf

Line(p+2)={b,b+n-i};

//line loop of the "little triangles"
If ( i < n-1 )
Line Loop(ll)={p,-(p+1),-s};
EndIf

Transfinite Line {p,p+2}=nosTH;

s1=s;
s=b-i+1;
a=b+2;
b=b+n-i;

If (i < n-1)
Line Loop(ll-1+n)={p+1,ss+n-2-i),-(p+2),-(s-1):-(s-n+i+1)};
EndIf

p=p+3;
ll=ll+1;

EndFor

Line Loop(ll-1)={p-3,-(p-1),-s1};


//Plane Surfaces
For i In{1:2*n-3}
Plane Surface(i)={i};
EndFor


//Transfinite surfaces ,only rectangules

a=2;
b=n+1;
c=2*n-1;
d=n;
s=0;

For i In{n:2*n-3}

Transfinite Surface{i}={a,b,c,d};

s=s+1;
a=b+1;
b=b+n-s;
d=c;
c=c+n-1-s;

EndFor

Recombine Surface{n:2*n-3};

//----------------------------------end-----------------------------//

Only need to change the geometry, the number of points, the number of nodes and ready to build the mesh around

greets
RM