PRojects

Effect of Leading Edge Root Extension (LERX) on Delta Wing Aerodynamics

 Delta wings, while advantageous in supersonic regimes due to their inherent stability and high lift-to-drag characteristics, suffer significant aerodynamic penalties during subsonic flight, particularly in terms of lift generation. The current study explores the effectiveness of Leading Edge Root Extensions (LERX) as a passive flow control device to enhance the subsonic aerodynamic performance of a slender delta wing. Parameters studied are the effects of Reynolds number, angle of attack, sweep, and roll angle. Measurements include aerodynamic forces and moments, Particle Image Velocimetry (PIV), and tuft-flow visualization.

Effect of Sinusoidal Trailing Edge for the Control of Reverse Flow on High-Speed Rotorcraft

Rotorcraft are essential assets in both general aviation and military applications due to their exceptional operational versatility. A significant limiting factor to the maximum forward speed is the onset of reverse flow at high advance ratios. During reverse flow, the sharp geometric trailing edge transitions into the aerodynamic leading edge, forcing an early flow separation. The flow separation generates higher drag, negative lift, and high pitching moment impulses, which affect the aerodynamic efficiency and the structural health of the rotor blades. The current study investigates the effects of various trailing-edge serration/sinusoidal geometries, as a passive flow control strategy, for the mitigation of these deleterious effects.  The study is being conducted for two-dimensional and three-dimensional blades at different sweep configurations and Reynolds numbers. Measurements include aerodynamic forces and moments, PIV, and tuft-flow visualization.

Effect of Propellers and Ducted-Propellers on Boundary Layer over a Surface

The project aims at investigating the upstream suction generated by propellers and ducted-propellers on boundary layer over surfaces like flat plate and wings. Next-generation aircraft consist of blended wing body (BWB) models with distributed propulsion. In a BWB model, the fuselage also works as a lifting surface. Hence, boundary layer ingestion-based, surface-mounted turbofan engines can potentially work as trailing-edge suction-based flow control devices. The project aims to study this flow control effect.  Parameters studied are the effects of the incoming boundary layer state, rotor advance ratio, rotor geometry, and rotor tip clearance. Measurements consist of surface pressure measurements and PIV. A parallel computational study will be conducted by Dr. Rajesh Ranjan (AE-IITK).

Effect of Orifice Geometry on Jets in Crossflow

A transverse jet issuing into the freestream produces a pair of counter-rotating vortices, which bring momentum into the boundary layer, thereby energizing it and helping in delaying or mitigating its separation. It is one of the most important and most investigated flow-control actuators. One of the parameters which affects the interaction of the jet in crossflow is the orifice geometry. The current study investigates a new class of novel orifice geometries, which may significantly affect the flow physics and actuation efficiency. Parameters studied are the effect of blowing ratio, momentum coefficient, state of the incoming boundary layer (laminar and turbulent), and the pressure gradient. Measurements primarily consist of PIV.

Control of Wingtip Vortices

Wingtip vortices develop at aircraft wingtips due to a pressure imbalance in the process of generating lift. They lead to induced drag, which accounts for 30-50% of the total aerodynamic drag of an aircraft at high lift configurations, such as during take-off and landing. These vortices are also a major source of turbulence for smaller trailing aircraft, which has led to several catastrophic accidents. In this project, a novel wingtip device is investigated, which may lead to weaker vortices that dissipate faster. This will help in attaining higher aerodynamic efficiency and lower wake turbulence. Parameters studied will be the effects of Reynolds number, angle of attack, and tip device geometry. Measurements include aerodynamic forces and moments, and PIV.

Effect of Surface Imperfections on Flow over a Slender Body

Surface imperfections can lead to an asymmetric flowfield over a slender body at high angles of attack. The flow asymmetry leads to unwanted side forces which can affect the trajectory and the stability of the body. This study aims to characterize these effects for surface imperfections of different heights. Parameters studied will be the effect of Reynolds number, angle of attack, and imperfection position and height. In future, the same study will be extended to a slender body with fins. Measurements will include aerodynamic forces and moments, oil-flow visualization, and PIV.