Fundamental Fluid Mechanics and Aeroacoustics Research
Aeroacoustics is a branch of fluid mechanics and acoustics that studies noise generation via either turbulent fluid motion or aerodynamic forces interacting with surfaces. We are tackling this difficult and important problem by solving complex and unsteady fluid dynamics and turbulent flows, and we are developing new theories and computational algorithms to predict the generation and propagation of aerodynamically induced noise. One example in this area is airfoil turbulent boundary layer trailing edge noise. We are developing efficient and accurate numerical methods to predict trailing edge noise. Our research contributes to advancing aerospace engineering and science, and fundamental knowledge and understanding of unsteady flows, turbulence, and aeroacoustics.
Rotorcraft Aerodynamics and Aeroacoustics
Rotorcraft has a unique capability of hovering and vertically taking-off and landing. However, rotorcraft noise is an issue in terms of public acceptance in urban surroundings and detection in military operations. We are using high-fidelity computational fluid dynamics (CFD) and computational structural dynamics (CSD) coupling simulations to compute aerodynamic forces, wake flows, and elastic blade motions. Based on the flow fields and trim solutions, we predict tonal and broadband noise that are generated from rotating blades. We explore new ideas to reduce rotorcraft noise, enhancing the public acceptance of rotorcraft in urban areas and mitigating the detection of rotorcraft in military operations. We are also investigating noise issues in transformative electric vertical take-off and landing (eVTOL) aircraft or urban air mobility (air taxi) system.
Wind Energy Aerodynamics and Aeroacoustics
Wind energy is exponentially growing globally and has recently become mainstream of energy and power. In order to further reduce the cost of wind energy and to accelerate the expansion of wind turbine installation, it is important to improve aerodynamic efficiency and to maximize the capturing of wind energy. In addition, wind turbine noise has been an issue in building permit in residential areas. Our lab is working on wind turbine aerodynamic and aeroacoustic research. We use computational fluid dynamics (CFD), reduced-order vortex methods, statistical turbulent models, and experimental wind tunnel tests to advance the technology and knowledge of wind energy. Our research contributes to next-generation environmentally friendly renewable energy.
Aircraft Engine or Turbomachinery Aerodynamics and Aeroacoustics
Aeroacoustic research has been begun with the introduction of aircraft jet engine in 1950s. Since then, fan and jet noise have become most important noise sources in modern aircraft engines. We are working on predicting fan and jet noise by using computational fluid dynamics (CFD) and statistical turbulent models. We explore new concepts to mitigate the engine noise. We are applying new technologies into both conventional ducted turbofan engines and next-generation open rotor or unducted fan engines. We are also working on the interaction of aircraft engine noise with a fuselage that is considered as an acoustic scattering problem or propulsion airframe integration.
We are grateful to our sponsors: NSF, US Army, Hyundai Motor Company, Korea Institute of Machinery and Materials (KIMM), UC Davis, etc.