Anyone has done Tumble ratio report in Star ccm?
 

Hello everyone,
Any of you has done Tumble ratio report? I have got tumble ratio of 0.002 from what I have done. It is clearly wrong. Hope any of you can point out what I have done wrong? Thank you

As the picture shows below, I am going to have the tumble ratio at engine speed of 4500rpm along the axis which is pointed out with star in this picture.
http://i198.photobucket.com/albums/a...ps4wtqm4qr.png

I created a Cartesian coordinate shows below, therefore Z aixs will be the aixs crankshaft spins.
http://i198.photobucket.com/albums/a...psglc7lgju.png

Settings:
http://i198.photobucket.com/albums/a...psx9rake1r.png

I am not sure what mean by Tumble origin. In tutorial says center of cylinder. But my axis is not at center.

Hi shaoyikai813,

Just want to clarify and ask, were you able to calculate tumble using this method of the report?

Unable to make this report work
 

Have you guys been able to use Tumble Ratio and to get reasonable values? I'm getting resoults like 0,00005

from looking at that old first vector scene image the user has not created the local csys at the required tumble center location and at the correct orientation. i have used this report in the past with success but you need to follow the help directions carefully. and a very low result might mean your engine has very low tumble of course

In the steve-portal there is a best practice guide for steady state port flow. In a nutshell there are the following points to consider:

• create a local coord-sys for the cylinder
• create a single region for the cylinder part (the displacement chamber)
• Always use the swirl report in ice-cases. Switch the coordinate to consider swirl or tumble (z-axis for swirl, x- and y-axis for tumble)

With that you get swirl = sum{rho_i V_i [(X_i-X_m)v_i-(Y_i-Y_m)u_i]} / (2 pi n/60 sum{rho_i V_i [(X_i-X_m)^2+(Y_i-Y_m)^2]} ) I think that is the same like pary07 looked for in antother thread.

For what do you need the tumble values? For further 1D-Simulations?