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 morteza08 August 18, 2010 07:47

suction boundary conditions

hi
I am trying to model suction over an airfoil in fluent and gambit.
but i encountered some problems that i can not find the solutions for since 2 weeks ago.
first:: i have read many articles that model continous suction or suction using a
synthetic jet.
all of the articles give us the suction velocity ,but when i choose the outer
boundary as pressure far field ,i see some warnings. some body tolds me that
i have to use the pressure outlet boundary condition for suction hole...
but i can not calculate the pressure for my low renolds number model...
in other words when i am trying to re-do an earlier numerical work in fluent that
used velocity inlet for suction,i also have tobe able to do it..
2; the drag coefficient is negative in nearly all cases and the lift coefficient
has a big variation with the exact value..and sometimes has a negative value.
3.i have modeled more than 7 different cases in gambit with differen meshes.
i do not know where do the problems come from?
a: which type of mesh is better for modelling a base airfoil and suction-including airfoil..
C-H grid....O-grid....boundary layer mesh or ....
please send me a dbs file of mesh over a base airfoil and a dbs file of mesh over a sutioned
airfoil...
b: please tell me which boundary conditions i have touse in gambit...
pressure far field,symmetry,wall or ...... for a typical C-H grid over airfoil please
express the boundary cond. detailed.
c: which solver and discretization schemes is better to model a base airfoil and
suctioned airfoil.
tell me the appropriate turbulance model and any other things you things is good to
better model an airfoil.
d: to calculatethe darg and lift coefficients in fluent , is it needed to change
the default value of area in refrence value?
e:please send me by email useful file(tyrorial,mesh file,dbs file ,case and data file or..)
thatcan help me to do this...thanks
i am ready to send you my works to tell me my faults..
but it isan emergency ..please sooner...
thanks