Nixon, D., "Control of Hypersonic Vehicles by Non-Geometric Boundary Conditions," SAE Technical Paper 2003-01-3033, 2003, doi:10.4271/2003-01-3033.
Almost all aerospace vehicles that depend on aerodynamic lift use changes in geometry for control. Examples include ailerons, elevators and flap deflections. As a theoretical concept these controls represent changes in one of the necessary boundary conditions for the solution of the Navier Stokes equations, which model the airflow. The complete boundary conditions require that the velocities and the temperature on the body surface be defined. In principle, the airflow can be changed by altering the temperature on the body surface. The effectiveness of controlling a vehicle by altering the surface temperature, which is equivalent to an extraction of energy from the airflow, is the topic of this research.