2 Replies Latest reply on Jan 2, 2013 12:24 PM by Rick McWilliams

    Shaping Aerodynamic Body

    Cme Root

      Hi.

       

      I would like to build the most aerodynamic shape i can get around the structure of the cabin of an aircraft i am designing. So,  i was thinking in solidworks do it for me automatically for me, not show me the results of the study and i change it myself by re-sketching, but solidworks automaticaly re-sketch the shape/surface for me.

      I saw the tutorial of a co2 car design at https://www.solidworks.com/sw/docs/CO2_Car_Design_WB_2011_SV.pdf where they did an aerodynamic body re-sketching manually, but i would like that solidworks shows me drawing/sketching a new surface.

       

      Maybe...

       

      1- Sketch a blank outside rectangle (the cabin surface/body) - SW will modify

      2- Sketch another retangle INSIDE the previous retangle representing the structure limits.

       

      3- Now, tell solidworks to modify the outside retangle creating an aerodynamic surface AROUND the inside retangle, respecting the space of the INSIDE/STRUCTURE retangle.

       

      Can we do this?

        • Re: Shaping Aerodynamic Body
          Bill McEachern

          in a word, no.

          • Re: Shaping Aerodynamic Body
            Rick McWilliams

            CFD software does an analysis of the geometry that you provide. You will need to learn some aerodynamics and the vocabulary of aerodynamics. Drag d= 1/2 rho V^2  S Cd.  S is the characteristic area usually planform area. Cd is the drag coefficient which depends on shape. V is the velocity. Rho is the density of air. 

             

            A good start for a low drag shape is a scaled in thickness airfoil shape NACA 66021. It is a highly laminar airfoil section. Use the airfoil shape. in one plane and another smooth shape for the profile view.  I build aerodynamic shapes using boundary surfaces. Use splines that have two or three control points, less is best. This will avoid wrinkles and ripples.

             

            Then use Solidworks flow to analyze the shape. Look for favorable pressure gradients on the surface to have a low drag laminar flow. Look at the velocity in a variety of planes. Perhaps show velocity iso surfaces at half the free stream velocity.  Shear is important but difficult to interpret.