Ongoing Research Projects - Jan 2020 - Present
Velocity magnitudes (a, b, c) and corresponding POD modes (d, e, f) at different actuation frequencies for a conventional flap
Investigation of Circulation Control Application on Trailing Edge Blowing
This ongoing study is directed towards exploring the effect of circulation control application on aerodynamic control surfaces to improve their operational efficacy. Recent work has been focused on the research of upper-surface trailing-edge blowing during flap actuation on a semi-span NACA 0012 planform using two different flap configurations – a conventional and a dual radius flap, respectively. Preliminary numerical simulations and experimental measurements have been carried for various angles of attack, flap deflection angles, Reynolds numbers and blowing intensities to investigate the steady-state flow physics for both flap configurations. Particle Image Velocimetry (PIV) is used with the snapshot Proper Orthogonal Decomposition (POD) method to understand various dominant structures associated with the mixing flows. The ongoing investigation of this circulation control application is also being pursued for different wing planforms such as the flying wing SACCON UAV platform in conjunction with innovative flap configurations acting as the trailing edge control surface composed of deformable structures that could further improve the efficacy of the installed circulation control device.
Wing-tail VLM computational model (above) and X-Plane representation (below) of the Apprentice S15e platform with symmetrical winglet deflection
Bio-Inspired Winglet Deformation Investigation on UAV platforms
Inspired by the dynamic spanwise wing deformation of avian fliers, this ongoing research attempts to characterize the effects of winglet deformation on flight performance, stability, and control. Recent work has been focused on the study of the effects on the lateral-directional stability of a small-scale Unmanned Aerial Vehicle (UAV) due to the wing tip folding for roll and directional control. Static stability parameters of symmetric and asymmetric winglet deformation have been obtained through analytical methods involving Datcom, Advanced Aircraft Analysis (AAA) software and Vortex Lattice Method (VLM) computations. Furthermore, representative flight modelling of the analyzed aircraft is undertaken in X-Plane’s flight simulator for verification of flight dynamic response with an implemented controller. Ongoing work attempts to further characterize these flight dynamic effects of wingtip morphing into a comprehensive mathematical model along with the flow-field investigation of different wing planforms operating at low Reynolds numbers, typical of small-scale UAVs, through Stereo-Particle Image Velocimetry (SPIV). Future work is aimed towards the development of a dynamic morphing winglet that ensures the utilization of the performance benefits of winglets across all phases of flight for varying Reynolds number applications.
Research or Creative Experience for Undergraduates (RCEU) Projects - May 2020 - August 2020
Computational structured mesh domain (above) and DRF flap with and without actuation (below)
Numerical Investigation of Active Flow Blowing on a Wing with Conventional and Non-Conventional Flaps
The project was directed towards investigating the effects of active trailing edge blowing with deflective flaps with numerical techniques. Active Trailing Edge (TE) blowing is a form of Active Flow Control technique which ejects high speed flow over the TE of the wing. AFC’s have the benefit of decreasing drag in low blowing regimes and significantly increasing lift in high blowing regimes. The former could be used to make extremely efficient, greener aircraft or decrease airport noise. The latter could aid in decreasing airport noise and decrease the footprint of landing strips which could aid in military deployment or humanitarian missions where landing strip areas are sparse. Computational Fluid Dynamics (CFD) was utilized to investigate the quantitative benefits of blowing. CFD is a numerical technique which approximates the Navier Stokes equations using a discretized domain called a mesh. The results of this work produced high fidelity velocity contours showing the vortex elimination due to blowing. Future works aim to calculate relevant coefficients on the time effects of deflecting the flap with blowing.
Winglet parameterization parameters (above) and predicted versus simulation results from optimization (below)
Small-scale UAV winglet optimization
The goal of the proposed work was to conduct the aerodynamic analysis and optimization of the winglet of a small-scale UAV to reduce the effect of wingtip vortices on aircraft performance. Each component of an aircraft can be broken down into its most basic physical parameters, such as the span or dihedral of a wing. Specifically, a winglet was broken down into its most basic parameters and a computational model was built using a three-dimensional parametric modeling software. In contrast to typical computer-aided design (CAD) models, the use of parametric models allows for rapid model adaptation to accommodate a range of fidelities for aerodynamic analysis. The proposed work used the developed parametric models to collect aerodynamic data and approximated the data using a nonlinear function in a curve fitting algorithm. An evolutionary global optimization algorithm was implemented to optimize the nonlinear function and find the winglet configuration that minimizes the induced drag of the small-scale UAV.
Research or Creative Experience for Undergraduates (RCEU) Projects - May 2019 - August 2019
Wind tunnel model (above) and symmetric actuation effects at 12kV (below)
Selective Dielectric Barrier Discharge Actuation for Flow Control of Delta Wings
The goal of the proposed project was to control the vortex formation over a delta wing surface, using selective Dielectric Barrier Discharge (DBD) actuation to improve the aircraft’s performance. DBDs or plasma actuators are electrical devices that generate a wall bounded jet without the use of any moving parts. In contrast to conventional DBD actuators driven by sinusoidal voltages, a voltage profile consisting of nanosecond pulses superimposed on dc bias voltage is proposed. The advantage of this non self-sustained discharge is that the parameters of ionizing pulses and the driving bias voltage can be varied independently, which adds flexibility to control and optimization of the actuators performance. The proposed work investigated the possibility of selectively manipulating vortex formation using nanosecond DBD’s over a delta wing to improve aircraft’s performance. Wind tunnel testing and flow visualization techniques such as Particle Image Velocimetry was used for evaluating the DBD’s efficiency. Effects of symmetric leading-edge DBD actuation in a post breakdown phase at x/c=0.5 shows a reduced region of increased peak vorticity for the right vortex along with the substantial strengthening of the left vortex which led to the reformation of the vortex core, consequently delaying vortex breakdown.
Optimized blended and multi-winglet (above), Lift/Drag Coefficient vs Angle of Attack for different cant angles (below)
Preliminary Analysis & Design of Morphing Winglets for UAVs
The goal of the proposed work was to conduct an analysis and develop a morphing (adaptive) multi-winglet capable of reducing the strength and size of wingtip vortices, resulting in improved aircraft performance. Induced drag accounts for roughly 40% of the total drag on an aircraft and therefore, reduction of the induced drag would significantly reduce fuel consumption, cost of operation, and the carbon footprint of the aircraft. Wingtip modifications can either move the vortices away in relation to the aircraft longitudinal axis or reduce their intensity. Morphing multi-winglets, where the geometry can be adjusted real-time to the changing flow conditions, have the potential to improve the aerodynamic performance during climb and/or high-speed off-design conditions by providing adapted wing lift distribution throughout the flight envelope. The developed adaptive winglet designs will subsequently be subjected to wind tunnel testing and Particle Image Velocimetry for optimization and performance analysis.
New Faculty Research (NFR) Program - December 2018 - December 2019
Morphing wing prototype and CAD (above), Flexinol actuator test setup (below)
Design and Development of an Actuation System for Morphing Wings
The goal of the proposed work is to design and develop a lightweight actuation system for a morphing flap capable of sustaining a smooth operation under aerodynamic loads. Using a morphing (adaptive) wing, whose geometry varies according to changing external aerodynamic loads, the airflow in each part of the aircraft mission profile can be optimized, resulting in an increase of aerodynamic efficiency during flight. The use of additive manufacturing techniques enables manufacturing parts with selective strength, toughness, and ductility by linking multiple types of topologies in the case of “lattice structures”. This, not only introduces a new degree of design freedom to build morphing structures with identical geometry but also allows it to bend in different ways. A morphing flap using shape memory alloy (SMA) actuators will be designed, developed and tested, while actuation optimization will be conducted through Particle Image Velocimetry analysis and wind tunnel tests.