Numerical study on the static and dynamic aerodynamic characteristics of cones with forced boundary layer transition

When a high-speed reentry vehicle enters the near space, the boundary layer undergoes the transition process as the Reynolds number increases. The boundary layer transition modifies the surface pressure and skin friction distributions on high-speed vehicles thus affecting the aerodynamic and stability characteristics. For instance, the asymmetric transition fronts on inclined axisymmetric vehicles induce extra force and moment, thereby affecting the vehicle's static and dynamic stability. Consequently, an investigation into the effects of boundary layer transition on aircraft's stability is critical for the design and control of high-speed vehicles. This paper analyzes the influence of boundary layer transition on the static and dynamic stability of a sharp cone using a high-speed numerical simulation software. This is accomplished by conducting numerical simulations of forced transition with different types of transition fronts by integrating RANS models and the forced pitching oscillation method. For this dynamic numerical simulation, a transition control surface is essential, constructed by extending the transition front from the cone surface in the wall-normal direction. Results show that as the transition front moves backward, the static stability decreases while the dynamic stability increases. The boundary layer transition introduces additional pressure and skin friction, with the former being the primary contributor to the overall induced pitching moment dynamic derivative.