Method for Improving Inlet Flow Quality

The ability to control the flow in the engines of aircraft in crossflow conditions is especially important for future aircraft equipped with ultra-high-bypass-ratio engines. This challenge is addressed computationally by employing the traverse actuation method to enhance flow quality in the inlets of turbofan engines and electric fans. This unsteady actuation is based on an array of discrete jets blowing in the general streamwise direction toward the fan face. The jets move in the circumferential direction. The continuous actuation produces small, fast-moving jet packets that travel laterally in a periodic manner, resembling the sideways motion of a crab. This spatial sweeping motion along the inlet surface provides extensive area coverage and is very effective in reducing flow separation in a quasi-steady manner. Special time-varying boundary conditions are used to simulate the traverse actuation. The efficiency of this flow control approach is demonstrated for an aircraft engine cowl in crossflow, where flow separation that originally develops on the windward side is effectively reduced or outright eliminated using a small level of actuation input. The study prioritizes low actuation input, which is essential for practical system integration. Actuator devices that provide the desired flow control patterns are also described.