Research
Hanson Lab · York University
Research Areas
Wind-tunnel experiments, optical flow diagnostics, turbulence generation, force measurements, and CFD — applied to transportation, sport, environment, and industry.
Vehicle Aerodynamics in Realistic Flow Conditions
This research investigates how vehicles respond to realistic on-road aerodynamic conditions, including turbulence, gusts, and changing yaw angles. By recreating these complex flow environments in the laboratory, we aim to improve understanding of drag, stability, wake structure, and aerodynamic performance under conditions that better represent real driving.
Demonstration of the active airfoil array
Cycling / Sport Aerodynamics
Our sports aerodynamics research investigates how textile roughness and seam placement influence drag, vortex shedding, and wake structure around cyclist limb-like geometries. Using wind-tunnel testing, force measurements, hot-wire anemometry, and particle image velocimetry, we study how fabric and seam design can trigger beneficial changes in flow separation.
The results show that well-designed textile and seam configurations can reduce drag substantially, with reductions of up to approximately 20% for most fabrics and approaching 45% for selected seam configurations.
Key Findings
- Textile roughness and seam placement influence flow separation and wake structure.
- Circular-cylinder tests provide a useful model for cyclist arms and legs.
- Selected seam configurations can substantially reduce aerodynamic drag.
- PIV measurements reveal how changes in the wake are linked to drag reduction.
- Effect of roughness and trips on the drag of a circular cylinder at subcritical flow — JWEIA 2024
- Vortex shedding from a yaw-oscillating circular cylinder in subcritical flow — Physics of Fluids 2025
- Spanwise wake structure of a yaw-oscillating circular cylinder at subcritical flow — JFS 2022
- Near-wake of a yaw-oscillating circular cylinder at subcritical flow — JFS 2022
Active Turbulence Generation
This research develops active methods for generating controlled turbulence in laboratory facilities. Using systems such as active grids, gust-generation mechanisms, and random-jet arrays, we create flow conditions with prescribed turbulence intensity, length scales, and unsteady behaviour. These tools allow us to study how complex turbulent environments affect aerodynamic performance, particle transport, and flow control.
Particle Transport in Turbulence
This work examines how fibres, rods, and microplastic-like particles move, orient, and settle in quiescent and turbulent flows. Experiments are designed to connect particle geometry, Reynolds number, turbulence intensity, and orientation dynamics to settling velocity and transport behaviour. The results support improved modelling of particle transport in environmental and engineering systems.
- A. Hamidi, D. Daramsing, M. D. Gordon, L. M. Jantunen, and R. E. Hanson, Low Reynolds number settling of bent rods in quiescent fluid, Fluids, 11.3:72, 2026.
- A. Hamidi, M. D. Gordon, L. M. Jantunen, and R. E. Hanson, Settling of U-shaped rods at low Reynolds numbers, Physics of Fluids, vol. 37, no. 7, 2025.
- A. Hamidi, D. Daramsing, M. D. Gordon, L. M. Jantunen, and R. E. Hanson, Terminal settling velocity of cylindrical rods of various shapes, Journal of Fluid Flow, Heat and Mass Transfer (JFFHMT), vol. 11, no. 1, pp. 240–247, 2024.
- A. Hamidi, D. Daramsing, M. D. Gordon, L. M. Jantunen, and R. E. Hanson, Straight and curved cylindrical rods settling in quiescent fluid with application to atmospheric microplastics, Experiments in Fluids, vol. 65, no. 6, p. 81, 2024.
Conference contributions
- H. Khanjari, A. Hamidi, and R. Hanson, Experimental analysis of wake dynamics: Detailed versus simplified geometry of a mine fleet heavy hauler truck, 6th International Conference on Experimental Fluid Mechanics (ICEFM), Niagara-on-the-Lake, Canada, May 20–22, 2025.
- A. Hamidi, M. D. Gordon, L. M. Jantunen, and R. E. Hanson, Horizontal drift and rotation of complex-shaped rods settling at low Reynolds numbers in a quiescent fluid, 6th International Conference on Experimental Fluid Mechanics (ICEFM), Niagara-on-the-Lake, Canada, May 20–22, 2025 (poster presentation).
- A. Hamidi, D. Daramsing, M. D. Gordon, L. M. Jantunen, and R. E. Hanson, Terminal settling velocity of cylindrical rods with various geometries applicable to atmospheric microplastics, 11th International Conference on Fluid Flow, Heat and Mass Transfer (FFHMT 2024), University of Toronto, Toronto, Canada, June 16–18, 2024.
- A. Hamidi, M. D. Gordon, and R. E. Hanson, The effects of various geometries of bent cylindrical rods on their terminal velocity applicable to atmospheric microplastics, Thousand Islands Fluid Mechanics Meeting, Ontario, Canada, May 10–12, 2024.
- A. Hamidi, D. Daramsing, R. Alishahian, E. Ward, R. E. Hanson, M. Gordon, and L. Jantunen, Aerodynamic behaviour of bent microfibers to support predictive modeling of atmospheric transport, ASME 2022 Fluids Engineering Division Summer Meeting (FEDSM2022), Toronto, Canada, August 3–5, 2022.
- D. Daramsing, A. Hamidi, R. Alishahian, E. Ward, R. E. Hanson, M. Gordon, and L. Jantunen, Aerodynamics of straight rods at low Reynolds numbers in a quiescent fluid to model settling of microfibers in the atmosphere, ASME 2022 Fluids Engineering Division Summer Meeting (FEDSM2022), Toronto, Canada, August 3–5, 2022.
- D. Daramsing, E. Ward, R. Alishahian, A. Hamidi, R. E. Hanson, M. Gordon, and L. Jantunen, Aerodynamics of microplastics: Quantifying transport towards predictive atmospheric modelling, 2021 Northern Contaminants Program Results Workshop, October 19–21, 2021 (poster presentation).
Active Flow Control
Active flow control uses small, controlled inputs to modify larger flow structures such as separated shear layers, vortices, wakes, and jets. Our work investigates synthetic jet actuators and actuator arrays to understand how forcing frequency, phase, and actuator configuration can influence jet vectoring, vortex formation, and wake behaviour.
Video demo coming soon
Industrial and Environmental Flows
Our research applies experimental and computational fluid mechanics to industrial and environmental flow problems. Current and recent projects include flow and mixing in electroless plating systems, wake modelling for large mining vehicles, ventilation-related transport, and the development of simplified analytical flow models.
Trombe Walls for Sustainable Buildings
Trombe walls are passive solar structures that reduce the heating and ventilation loads of HVAC equipment, especially in colder climates. While passive solar structures are frequently studied outdoors, various researchers have conducted experiments on indoor, laboratory-controlled passive solar structures — several of which rely on electric heating to deliver a steady-state, uniform heat flux as a substitute for the transient, non-uniform sunlight absorbed within the air channel that drives natural convection.
Related experimental studies of turbulent natural convection within asymmetrically heated, parallel-plate vertical air channels have extensively characterized the airflow at heights applicable to residential buildings. These studies are used to validate our CFD models, which support parametric studies comparing the heat transfer performance of different Trombe wall channel thicknesses. The results below show the validation of an SST k-ω model against published experimental data.
This project is led by MASc student Sebastian Bissainthe-Vandermeer and is co-supervised with Prof. Paul G. O’Brien (Department of Mechanical Engineering, York University).
