what will be the exact boundary condition for 2d and 3d airfoil.I had plotted in side a rectangular domain.there are 2 and 3 air foil togethar

Hi, The following boundary conditions may be adopted for any kind of air foils

a. at the surface of the airfoil it is no penetration condition b.in the far field region we have free stream velocity unchanged c. at the inlet and outlet u can have either velocity or pressure boundary conditions.

for further details u can see any basic aerodynamics book it is specified in the first or second chapters only

bye

Hi sumitha,

Pressure far field is the only boundary condition u have to spcify and angle of attack for X, Y component.......

Regards, Vijay

But its not taking farfield condition

Hi,

For far field condition the domain should be large enough these are the things given the manual for farfield just go through it

Pressure far-field conditions are used in FLUENT to model a free-stream condition at infinity, with free-stream Mach number and static conditions being specified. The pressure far-field boundary condition is often called a characteristic boundary condition, since it uses characteristic information (Riemann invariants) to determine the flow variables at the boundaries.

! This boundary condition is only applicable when the density is calculated using the ideal-gas law (see Section 7.2). Using it for other flows is not permitted. To effectively approximate true infinite-extent conditions, you must place the far-field boundary far enough from the object of interest. For example, in lifting airfoil calculations, it is not uncommon for the far-field boundary to be a circle with a radius of 20 chord lengths.

if ur boundary is not far u can use this u should use pressure boundary condition at the outlet specifying the outlet pressure which u can predict it by Bernoulli principle.

hope this works out

bye

or u can also use outflow boundary conditions

# Pressure far-field boundary conditions are used to model a free-stream compressible flow at infinity, with free-stream Mach number and static conditions specified. This boundary type is available only for compressible flows.

# Outflow boundary conditions are used to model flow exits where the details of the flow velocity and pressure are not known prior to solution of the flow problem. They are appropriate where the exit flow is close to a fully developed condition, as the outflow boundary condition assumes a zero normal gradient for all flow variables except pressure. They are not appropriate for compressible flow calculation