The good thing about Bernstein polynomial, and CST itself is that later you will see that the smoothness of its curve is beneficial for optimization purpose! Since the number of parameters can be tuned easily by altering the order of Bernstein polynomial, CST is suitable for either conceptual or preliminary design of airfoil.Īlright, let’s kick out the jams and move to the mathematical expression. Roughly speaking, you also don’t want a bumpy airfoil, well, except if you want to add some shock bump on your airfoil. For simplicity purpose, this simple article considers only CST for the two-dimensional shape of an airfoil.ĬST build the airfoil by summing the individual contribution of its basis function that is elegantly built by Bernstein Polynomial. The greatest thing from CST is that CST can be used not only for an airfoil, but it can also be extended further into the general shape of aerodynamic bodies. Those are some of the reasons of why Brenda developed CST that is very simple to be coded and also it doesn’t take such a long time to understand the concept of CST itself. So what’s the point of having another airfoil parameterization method? As it was pointed by Brenda in her paper (Brenda is a woman engineer, cool!), we want an intuitive, robust, smooth, and flexible parameterization method. The Class Shape Transformation (CST) parameterization method was first developed by Brenda Kulfan, an aerodynamic engineer at Boeing.
Short note on CST method for airfoil parameterization ( MATLAB Code included)