Student Research Symposium

The Student Research Symposium features research presentations from trainees in NSERC’s Collaborative Research and Training Experience (CREATE) Program in Environmentally Sustainable Aviation. It is an opportunity for industrial and academic partners of UTIAS to network with each other, learn about current research at the institute, and meet prospective graduate interns. CREATE Trainees engage in one or two four-month internships. Some presentations will include discussion of work completed at industrial internships, along with their thesis research at UTIAS.

Date:   Friday, October 16, 2015
Time:  
9:00am – 6:00pm 
Location:
Lecture Hall, University of Toronto Institute for Aerospace Studies
4925 Dufferin St, Toronto, ON, Canada  M3H 5T6
Contact: sustainable.aviation@utias.utoronto.ca or 416-667-7796


Schedule

9:00     Registration and coffee

9:30     Keynote address: Martin Peeters,
            Pratt & Whitney Canada
               Gas Turbine Design Systems

10:30   Student presentations

Shahriar Khosravi (Prof. David Zingg)
Aerostructural Optimization of Non-planar Wings andUnconventional Aircraft Configurations

Timothy Chau (Prof. David Zingg)
High-Fidelity RANS-Based Aerodynamic Shape Optimization of Unconventional Aircraft Configurations

Hajar Pourbafrani (Prof. Heather MacLean and Prof. Bradley Saville)
Environmental Modelling of Fischer Tropsch Renewable Diesel Production

Dominic Lallier-Daniels (Prof. Stephane Moreau)
Analysis of Tip Leakage Flow Noise Inception in Axial Fans

12:15    Lunch

1:15      Student presentations

Derrick Chow (Prof. Philippe Lavoie)
Flow Characterization of Yawed Tandem Cylinders: A Step towards Landing Gear Noise

Philip McCarthy (Prof. Alis Ekmekci)
Investigation into the flow topology around a simplified two wheel landing gear model

Ross Cruikshank (Prof. Philip Lavoie)
Design of a control system for vortex shedding behind a blunt trailing edge airfoil using synthetic jets

Marc-Andre Theberge (Prof. Alis Ekmekci)
Passive Control of Wing-Body Junction Flows

2:45     Coffee break

3:00     Student presentations

Bharat Bhaga (Prof. Craig Steeves)
Compressive Instabilities in nanocoated microtrusses

Steven Chung (Prof. Craig Steeves)
Topology optomization of hybrid microtrusses

Valentin Stolbunov (Prof. Prasanth Nair)
Greedy Learning Algorithms for Large Data

4:00      Round-table discussion

5:00      Wine & cheese reception


Presentations

Bharat Bhaga, PhD Candidate                              April 2016
CREATE Trainee in Environmentally Sustainable Aviation
Compressive Instabilities in Nanocoated Microtrusses

Hybrid nanocrystalline microtruss structures are lightweight structures that can be used to decrease the structural weight of aircraft. These lightweight structures combine the benefits of both the high-strength capabilities of nanocrystalline materials, as well as the structural efficiency of microtruss structures. Nanocrystalline metals are those that have grain sizes smaller than conventional metals used in structural applications today, and have increased strength and wear resistance relative to conventional metals. Three-point bend tests on hybrid nanocrystalline microtrusses have shown that their failure mechanisms are driven by compressive instabilities. The compressive instabilities of these structures have not yet been investigated in detail. Thus, it is warranted that this area of research be pursued in order to better understand the failure mechanisms associated with nanocoated microtruss structures. The thesis project of interest will examine the compressive instabilities associated with hybrid nanocrystalline microtrusses and quantify new modes of failure that may be found. Information from these studies will be used to reduce the weight of these structures through optimization methods. Finite element models of nanocoated microtrusses will be compared to compressive tests of specimens, and optimization will be undertaken to minimize the weight of these structures. Since reduced structural weight contributes to decreased fuel burn, the data generated from this project will contribute to the goals of sustainable aviation.

Bharat completed an internship at Pratt & Whitney Canada in the Research and Technology department. He will discuss his internship in his presentation. 

Derrick Chow, MASc Candidate                                   August 2016
CREATE Trainee in Environmentally Sustainable Aviation
Flow characterization of yawed tandem cylinders: A step towards landing gear noise control.

The growing problem of aircraft noise-related health effects on the population surrounding airports serves as motivation for my study on landing gear aerodynamics and aeroacoustics. Experiments are performed on yawed tandem cylinders as a canonical model for landing gear with support struts. The main test facility is an open-loop, open-jet wind tunnel with an anechoic test section. Tests are conducted at freestream Reynolds numbers of 100,000 – 200,000, corresponding to Mach 0.15-0.30. The angle between the two cylinder axes is variable between 0 and 45 degrees, and the cylinders are instrumented with surface microphones along their spans to inspect the unsteady surface pressure spectra. Particle Image Velocimetry is used to quantify the flow structures around the leading cylinder and how they impact the trailing cylinder. This velocity field data is correlated with the surface pressure measurements to determine the flow structures that create large pressure fluctuation events. As well, far-field microphone arrays are being developed to look at noise propagation. In the medium term, there are plans for flow control tests to target the aforementioned flow structures in an effort to reduce the magnitude of surface pressure fluctuations and hence the far-field noise.

 

Steven Chung, PhD Candidate                                     April 2018
CREATE Trainee in Environmentally Sustainable Aviation
Topology Optimization of Hybrid Microtrusses

Hybrid microtruss structures have a high strength-to-weight ratio, making these structures attractive for use in aerospace applications such as aircraft structural components. Through strategic placement of voids in a material, the density of the material can be reduced greatly without a large trade-off in strength; this results in very efficient structures. By combining this structural efficiency with the material efficiency of nanocrystalline metals, high strength materials with low densities can be achieved. However, hybrid microtrusses have been observed to have a propensity to fracture at the microtruss nodes, resulting in specimens with a significantly lower strength than predicted. Through structural topology optimization, a method of structural optimization which allows the topology of the solution to vary by introduction and elimination of voids, it is possible to generate optimized microtruss topologies which have reduced stress concentrations and therefore, in theory, a reduced propensity for nodal fracture. These optimized solutions have complex topologies, and therefore fabrication of specimens will involve rapid prototyping out of polymer and subsequent coating in nanocrystalline metal by electrodeposition. Topology optimization algorithms will be developed to reduce stress concentrations in various 2D and 3D problems, and the optimized solutions for various problems will be fabricated as described above. The performance of optimized samples will be compared to finite element models as well as the performance of non-optimized samples in order to validate the optimized solutions.


Ross Cruikshank, PhD Candidate                            August 2018
CREATE Trainee in Environmentally Sustainable Aviation
Design of a control system for vortex shedding behind a blunt trailing edge airfoil using synthetic jets

Ross Cruikshank’s research involves the development of a control system for vortex shedding in the wake of a blunt trailing edge airfoil using synthetic jet actuators. The motivation for research into this airfoil shape is its high structural stiffness, and its ability to produce more lift than conventional thick airfoils. The major penalty associated with the use of blunt trailing edge airfoils is large fluctuating aerodynamic forces due to vortex shedding in the wake region. Previous research has identified a small scale instability in the wake of blunt trailing edge bodies that has been linked to the disorganization of the shedding vortices. It has further been demonstrated that an active flow control scheme that interacts with the small scale instability, using an array of actuators at the trailing edge spaced to match the spanwise wavelength of the instability, is effective at reducing fluctuating aerodynamic forces for Reynolds numbers (based on airfoil thickness) up to 5,000. The objective of the current research is to apply this control technique at Reynolds numbers greater than 5,000, and to determine the power requirements for control at these higher Reynolds numbers.

Shahriar Khosravi, PhD Candidate                               April 2017
CREATE Trainee in Environmentally Sustainable Aviation
Aero-structural Optimization of Non-planar Wings for Commercial Transport Aircraft

My research involves applying a high-fidelity aero-structural analysis and optimization tool to non-planar wings and unconventional aircraft configurations. In a non-planar wing, the wake leaving the system has a vertical structure. These systems can substantially reduce the induced drag which typically accounts for 40% of the total drag of a conventional tube-and-wing aircraft. Winglets, c-wings, and rectangular closed-wing systems are examples of non-planar wing systems. The closed-wing system, in particular, can reduce the induced drag by 46% in comparison to an elliptically loaded planar wing. Unconventional aircraft configurations can also achieve significant reductions in drag. The blended-wing body concept, for instance, has been estimated to achieve a 27% improvement in total fuel burn. Other possible unconventional configurations include truss-braced and high aspect ratio wing systems. Applying aero-structural optimization to these unconventional design concepts will make them economically viable alternatives to the existing designs by improving their performance even further.

Philip McCarthy, PhD Candidate                August 2016
CREATE Trainee in Environmentally Sustainable Aviation
Investigation into the flow topology around a simplified two wheel landing gear model

Philip McCarthy’s research is focussed on experimentally investigating the unsteady flow topology around a two wheel aircraft landing gear. The aim of this research is to gain an understanding into the fundamental sources of landing gear noise, from the perspective of studying the generation of turbulent structures caused by model geometry and flow interactions. The primary experimental facility used for this investigation is a recirculating water channel, analogous to a wind tunnel, which permits the use of advanced laser diagnostic techniques for unsteady velocity field/volume analysis. Acoustic data measured in an anechoic wind tunnel is also used to correlate the observed velocity measurements with the locations of noise generation in pursuit of fulfilling the research aim. This research is being conducted in collaboration with the Acoustics and Vibration department of Bombardier Aerospace. The research outcomes will be used to define best practise for designing future low noise landing gears as well as a source of validation data for computational fluids and acoustics software.

 

Valentin Stolbunov, PhD Candidate                       August 2018
CREATE Trainee in Environmentally Sustainable Aviation
Greedy Learning Algorithms for Large Data

My field of research is CFD. My PhD thesis would be dealing with Computational Turbulent Combustion and its applications in gas turbine engines.

I will be developing an adjoint-based error estimation and sensitivity analysis algorithm in combination with an anisotropic adaptive mesh refinement (AMR) technique. These would be incorporated into a 3-D fully turbulent Finite Volume LES solver for solving turbulent combustion problems. Various turbulence models would be used to model the subgrid scales and flame models would be used to model the chemical reaction rates. The solver would be used to model combustion instabilities occurring in combustors in aircraft as well as industrial engines. These instabilities are responsible for reduced efficiency and sometimes even failure of the component.

Part of my work would also focus on the development of explicit filters for LES. For implicit filters used in LES, the commutation errors are at best second order. In order to make the use of higher order spatial reconstruction and time-marching techniques, the order of this error must increase. This calls for the use of explicit filtering techniques which decouple the filter and mesh sizes.

 

Marc-André Théberge, M.A.Sc. Candidate                                April 2016
CREATE Trainee in Environmentally Sustainable Aviation, University of Toronto
Passive Control of Wing-Body Junction Flows

The objective of my research is to decrease the size and strength of horseshoe vortices that form at wing-body junctions, as these vortices have an adverse effect on aerodynamic and thermodynamic performance. This flow phenomenon occurs at all junction flows such as at turbine-blade hub junction, pin fins within channels or nozzles, guide vanes in gas turbine engines, and bases of bridge piers.  Horseshoe vortices, are vortices that form when a boundary layer (either laminar or turbulent) interacts with an obstacle protruding from the surface, upstream of the obstacle. The passive control method that is currently being investigated in a recirculating water tunnel, is the use of flat plates of different geometries placed ahead of the leading edge at the junction. The geometries that are tested consist of several triangular plates, with varying lengths (in the upstream direction) and thicknesses. Each of these plates is tested at a range of Reynolds numbers with a maximum of approximately Rec= 200,000 (based on chord length). By the use of particle image velocimetry, we are able to accurately track the strength and position of the vortices for unsteady conditions, thus being able to quantitatively determine the effects of the control method on decreasing heat transfer and local skin friction drag.