CFD Online Discussion Forums

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   Main CFD Forum (https://www.cfd-online.com/Forums/main/)
-   -   why my drag coefficient still over large (https://www.cfd-online.com/Forums/main/66064-why-my-drag-coefficient-still-over-large.html)

nuimlabib July 4, 2009 09:00

why my drag coefficient still over large
 
hii...for all
i am simulate airfoil with 2D model. i still confuse that in refernce values there are any parameter is area (m2), length(m) and depth(m)..what should i fill the box...that i change the area with value more than 1..the drag coefficient is better ( mean smaller) than using 1...why? can explain me...

Ahmed July 4, 2009 14:09

Quote:

Originally Posted by nuimlabib (Post 221460)
hii...for all
i am simulate airfoil with 2D model. i still confuse that in refernce values there are any parameter is area (m2), length(m) and depth(m)..what should i fill the box...that i change the area with value more than 1..the drag coefficient is better ( mean smaller) than using 1...why? can explain me...

1- write down the definition of the drag coefficient
http://en.wikipedia.org/wiki/Drag_coefficient
2- write down the equation for calculating the drag force, the basic equation, not the one given on the wiki, i.e., the integral over the area of the shear stress at the wall
3- answer your question by yourself
Good luck

nuimlabib July 5, 2009 23:27

1 Attachment(s)
the chord length of my airfoil is 1 m, with 2D model...so what fill box must i fill in parameter area..in reference value tool box..that the default value is 1..but result of the drag coefficient not accurate enough..what this is influence for drag coefficient..pleace give me more information


All times are GMT -4. The time now is 04:59.