Computer-implemented method for simulating flow of fluid around solid object

Patent metadata

Field	Value
Publication number	US-9449125-B2
Application number	US-201314054415-A
Country	US
Kind code	B2
Filing date	Oct 15, 2013
Priority date	Nov 16, 2012
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

A computer-implemented method for simulating a flow of fluid around a solid object comprises: defining straight lines between gravity points of elements in a solid object region and gravity points of elements in a fluid region; defining intersecting points of the straight lines with a boundary surface between the two regions; calculating distances between the intersecting points and the gravity points in the fluid region; and obtaining the shearing stress at the boundary surface.

First claim

The invention claimed is:

1. A computer-implemented method for simulating a flow of fluid around a solid object comprising the steps of:
defining a space model of a space is defined, wherein the space model is made up of elements have gravity points;
defining a boundary surface in the space model, wherein the boundary surface is between a solid object region of the space model in which a solid object model is defined and a fluid region of the space model which is outside the solid object region and in which a fluid model is defined;
defining straight lines extending across the boundary surface, wherein each of the straight lines extends between a pair of the adjacent gravity points which are one of the gravity points of the elements in the solid object region and one of the gravity points of the elements in the fluid region;
defining an intersecting point of each of the straight lines with the boundary surface;
calculating for each of the straight lines, the distances between the intersecting point and the gravity point in the fluid region;
obtaining the shearing stress between the fluid model and the solid object model at the boundary surface by using the following equation (1)

τ
⁡

(
correct
)

=

μ
⁢

u
⁡

(
live
)

-

u
⁡

(
boundary
)

dist
⁡

(

live
⁢

⁢
cell
⁢

⁢
to
⁢

⁢
boundary

)

⁢
A

,

Equation
⁢

⁢

(
1
)

wherein
τ(correct) is the shearing stress between an element whose gravity point is in the solid object region and an element whose gravity point is in the fluid region,
U(live) is the velocity of the gravity point in the fluid region,
U(boundary) is the velocity of the intersecting point between the boundary surface and the straight line extending between the gravity point in the solid object region and the gravity point in the fluid region,
dist(live cell to boundary) is the distance between the gravity point in the fluid region and the intersecting point,
μ is the shear viscosity of the fluid, and
A is the area of a section of the boundary surface crossing at least one of the two elements whose gravity points are in the solid object region and the fluid region;
judging if physical quantities of the space model are acceptable;
changing the design of the solid object model in order to reexecute the aforementioned steps when the physical quantities are not acceptable; and
outputting data about the space model in order to actually design the solid object based on data about the solid object model when the physical quantities are acceptable.

2. The fluid simulation method according to claim 1 , wherein,
in the equation (1), instead of the dist(live cell to boundary), dist′(live cell to boundary) modified by using the following equation (2) is used:
dist(live cell to boundary)= L 1×α(new)

α(new)=−0.54α 3 +0.9825α 2 +0.4661α+0.08   Equation(2)

wherein
L 1 is the length of the straight line, and
α is the ratio of dist(live cell to boundary) to the length L 1 .

3. The fluid simulation method according to claim 2 , wherein
the α(new) in the equation (2) is in a range of from 1 to 20, and
when α=0, the α(new) is in a range of from 8 to 20.

4. The fluid simulation method according to claim 3 , wherein
the Neumann boundary condition is defined as the pressure boundary condition for the boundary surface.

5. The fluid simulation method according to claim 2 , wherein
the Neumann boundary condition is defined as the pressure boundary condition for the boundary surface.

6. The fluid simulation method according to claim 1 , wherein
the Neumann boundary condition is defined as the pressure boundary condition for the boundary surface.

Assignees

• Sumitomo Rubber Ind

Inventors

• Tsunoda Masaya
• Yadav Arjun

Classifications

• G06F30/23 Primary

  using finite element methods [FEM] or finite difference methods [FDM] · CPC title

• G06F17/5018 Primary

  Physics · mapped topic