Understanding Airflow At Transonic Speeds

The complex unsteady airflow characteristics of certain aircraft features, such as landing gears and weapon bays, produce pressure fluctuations that reach unacceptable levels for operation and safety at transonic speeds.

To better understand how to control the airflow for pressure fluctuations and noise reduction, Awatef Hamed, Ph.D., Bradley Jones Professor and department head of Aerospace Engineering and Engineering Mechanics at the University of Cincinnati, leveraged the computational resources of the Ohio Supercomputer Center to develop and validate a hybrid unified turbulence model for the Detached Eddy numerical simulations of the unsteady Navier-Stokes equations.

“We worked to simulate and access active flow control using steady and pulsed fluidic actuation for acoustic suppression in transonic flow over an open cavity,” Hamed said. “We developed and implemented a new unified methodology to resolve both aerodynamic and aero-acoustic fields to study acoustic control.”

Hamed’s research team conducted high-fidelity simulations of supersonic cavity flow with active flow control and compared the results to experimental data and to LES results to assess the fidelity of the hybrid model. They also analyzed the influence of Reynolds number (the ratio of inertial forces to viscous forces) on the unsteady cavity flow and acoustic fields with and without control.

The resulting simulations illustrated that her methodology provides a useful tool for predicting complex 3-D separated unsteady flows over an expansive dynamic range at high Reynolds number and are comparable to LES predictions at one-sixth to one-tenth the CPU resources.

Project lead: Awatef Hamed, University of Cincinnati
Research title: Hybrid RANS/LES simuations of transonic cavity flow with control
Funding source: Ohio Space Grant Consortium