Moving measurements: Measurements of the turbulent/non-turbulent interface of a round jet in a co-moving frame of reference

At the turbulent/non-turbulent interface (TNTI) of a jet flow, momentum is transferred from the turbulent jet fluid to the fluid at rest. This transfer is governed by two mechanisms. One of them is related to the large scales of the flow and the other relates to the small scales of the flow. Which of the two is dominant is still a point of...

Quantitative Analysis of Flame Kinematics in Premixed Hydrogen-Air-DNG Jet Flames using PIV Measurements and Flame Front Segmentation

Today's electricity supply falls short of current demands, leading to the utilization of gas turbines in both ground based and avionic infrastructures. Nevertheless, these often rely on carbon-based fuels, resulting in escalating CO2 emissions. However, adopting hydrogen as a fuel eliminates carbon emissions. Aside from zero carbon emissions,...

Aerodynamics of cylinders in tandem: Experimental investigation by stereoscopic PIV

This thesis investigates the aerodynamics of two finite wall-mounted cylinders in tandem, focusing on drag reduction as a function of governing parameters.<br/>For the experimental wind tunnel campaign, two measurement techniques were employed: balance measurements and stereoscopic particle image velocimetry. While balance measurements exhibited...

Propeller Slipstream Characterisation by Large-Scale PIV: An experimental study for Isolated Propeller and Propeller-Wing Interaction

This study explores the flowfield around a pusher propeller-wing configuration using Lagrangian Particle Tracking (LPT). It assesses LPT’s capability to characterise propeller-wing interactions, emphasising its ability to resolve complex flow dynamics.<br/><br/>The experiment successfully achieves high particle concentrations downstream of the...

Experimental investigation of overflowing over river groyne exposed to primary ship-induced waves

Groynes in the Lower Elbe estuary in Germany are subject to attack from overflowing long-period primary ship-induced waves. Damage can occur on the crest and lee side of the structure due to the high turbulent overflowing flow velocities. An actual design tool for groynes exposed to overflowing primary ship waves is not yet present. Therefore,...

Lift Coefficient of an Accelerating Wing with Ground Effect

A F1 car is always in a dynamic flow when racing. The most common case would be acceleration, deceleration and turning a corner. Due to the new rule by FIA since 2021, ground effect is much more significant for F1 car. Limited by the experimental set-up of F1 teams, flow under the car and accelerating flow are hard to be measured quantitatively....

Drag reduction of bluff bodies in tandem: Size and spacing effects on cylinders and cyclists

In cycling, the presence of drag reduction from drafting, when multiple cyclists ride in tandem, is a considerable area of performance enhancement for a cycling team and the customisation of this tandem group has the potential of maximising the drag reduction for the entire group or a specific cyclist. The flow interactions between two tandem...

Pulsed jet arrays for turbulent separation control: An experimental study

An experimental investigation is presented in which an array of pulsed jet actuators is used to control a turbulent separation bubble formed on a curved backward facing ramp. The array is positioned upstream of detachment and consists of wall-normal high aspect ratio skewed rectangular jets which generate streamwise vortices in the boundary...

Experimental Study on Laser-induced Near-wall Cavitation via Particle Image Velocimetry

The fundamental research of cavitation has been a hot topic for decades, while a particle image velocimetry (PIV) measurement on single bubble dynamics is uncommon due to many technical hassles. The involved flow field is small in space and highly unsteady in time, so it challenging the spatial and temporal resolution that current PIV techniques...

PIV Experimental Comparison of Vertical Axis Wind Turbine Wake with Theoretical Models

Vertical Axis Wind Turbine (VAWT) operation is characterized by complex and unsteady three-dimensional fluid dynamics, which presents considerable challenges. One of the crucial points to understand is the complex interaction between rotor, inflow, and wake systems. If we can demonstrate its effectiveness in the complex flow/inflow conditions,...