Home / Examples / Fluid Analysis [Bernoulli] / Example18: Flow Around Spinning Top
With the moving wall condition, the flow around the spinning top is calculated.
Velocity distribution, velocity vectors, streamlines, and wall torque are solved.
Unless specified in the list below, the default conditions are applied.
Results will vary depending on Femtet version and the PC environment.
Item |
Settings |
Solver |
Fluid Analysis [Bernoulli] |
Analysis Space |
3D |
Analysis Type |
Steady-state Analysis |
Unit |
mm |
Set the Mesh Tab as follows.
Tab |
Setting Item |
Settings |
Mesh |
General mesh size: |
Specified by 20 [mm] |
Body Number/Type |
Body Attribute Name |
Material Name |
5/Solid |
Top |
002_Polycarbonate(PC) * |
6/Solid |
Air |
000_Air * |
* Available from the material DB
Moving Wall is set in the body attribute of Top.
Body Attribute Name |
Tab Name |
Settings |
Top |
Solid |
Solid Wall Type: Moving Wall Wall Motion: Rotation Vector of Axis: 0.0, 0.0, 1.0 Coordinate of Axis: 0.0, 0.0, 0.0 Angular Velocity: -1000 [r/min] |
Boundary Condition Name/Topology |
Tab |
Boundary Condition Type |
Settings |
Ground/Face |
Fluid |
Solid Wall |
|
Outer Boundary Condition |
Fluid |
Inlet/Outlet |
Natural Inflow/ Natural Outflow |
The vectors of the flow velocity distribution are shown below.
The vectors in the XZ plane at Y=0 are shown below.
Two whirlpools can be observed under the spinning top as below.
The value of the wall torque is in the table.
The wall torque is 1.314e-4 [N m].
The decrease in velocity due to the air resistance can be observed.