Invention:
This invention is novel flow control techniques for modifying the natural to turbulent transition process of the flow in the boundary layer of vehicles, projectiles, or missiles at supersonic/hypersonic speeds. This invention is concerned with delaying the onset of transition and the subsequent breakdown to turbulence as far downstream on the vehicle as possible. As the transition process in high-speed boundary layers is associated with strong unsteadiness, large pressure fluctuations, and intermittency, it may also be beneficial to accelerate transition to quickly establish a fully turbulent state. The key component proposed in the invention is "Imbedded Compact Control Actuators” (ICCAs) which will delay or prevent entirely the negative effects caused by the boundary-layer transition, including the detrimental effects of the unsteadiness in flow. This proposed technology will alleviate skin friction and wall-heating to increase payload and range of the specified vehicle while also reducing cost and weight of the vehicle.
Background:
The fluidic state of the boundary layer, laminar, transitional, or turbulent, determines the degree of skin friction and heating of high-speed vehicles. The drag caused by skin friction contributes a large portion to the total drag of a high-speed vehicle. Higher drag reduces the range and/or maximum payload of the vehicle. High wall-heating requires special materials that are very expensive and/or require Thermal Protection Systems (TPS) that add to the weight of the vehicle so that the maximum payload and/or the range of the vehicle is reduced.
Applications:
- High-speed aerodynamics
- Projectiles/missiles
Advantages:
- Alleviates skin friction and wall-heating
- Reduced weight
- Less expensive production cost
- Better range
- Increase in possible payload
