The present invention provides a method and a system for determining forces which act on a body with a controlled volume which is provided inside the flow tunnel and in which the body is arranged. A first measuring means is used to measure a pressure distribution for each surface defining the controlled volume. A second measuring means measures a velocity field for each defining surface of the controlled volume. Furthermore, a calculation unit is provided for calculating the forces acting on the body as a function of the pressure distributions and velocity fields measured for the defining surfaces of the controlled volume.