Abstract
In the inverse analysis, it is important to compute the gradient of the function. In the ordinary computation, this is a very complicated task. In this paper the authors propose the application of automatic differentiation (AD) as a new approach applied to the optimal control problems. The drag force minimization problem jetting the flow behind a circular cylinder is treated in this research. The forward mode AD computes the partial derivatives according to the differentiation rule of a composite function whenever basic operation is performed.