hellow, i whould like to know how to obtain the vertices coordinates of a rectangular geometry domain in order to compute the aerodynamic performances of a symmetrical NACA airfoil.please, i will be very grateful to receive any idee or commentary .thanks.

Are you asking how to choose the location of outer boundary ? That depends on your outer boundary condition. If you just keep the flow solution fixed, then you need to put the boundary at a very large distance from the airfoil, something like 100 chord. If you use a good boundary condition like those based on characteristics then you could put it closer. Using a point vortex correction allows to put the boundary still close something like 20 chords away. You can experiment for yourself. Compute lift and drag coefficients with different outer boundary locations and see how they vary.

wellcome Praveen. To explain, I have to create script files (file.txt), which can be read in ICEMCFD, in order to generate geometry, domain of computing and create mesh. I have done the aerofoil family. But to define: paroi 1 , paroi 2, inflow and outflow families I have difficulties to get the vertices(4) (x, y)coordinates of the rectangular( or square) domain of computing.I have idea to compute them with consideration of:c=100mm,longer of(square)domain=10c.In this case i need to know how to compute the (x,y) of the center of gravitation of the aerofoil.thanks in advance.