The Impact of Interstitial Air Pressure on Sand Acoustic Emissions in the Context of Mars Exploration

Desert sand acoustic emissions are produced when a “sonic sand” is sheared locally or by a natural dune slipface avalanche, resulting in a brassy sound between 50 and 400 Hz. This type of sediment exhibits particular granulometric, shape and surface characteristics, due to the grains’ erosion and transport history, and emits sounds when the...

Wall-normal pores for turbulent drag reduction: Experimental investigation into drag performance and flow mechanics

Flat surfaces with arrays of wall-normal pores called micro-cavity arrays have shown potential to reduce turbulent skin friction drag. Their designs have been inspired by acoustic liners which are sandwich panels consisting of a honeycomb core, a perforated top plate and a solid back sheet used on...

A Numerical Investigation into Transonic Flight on Mars Utilizing a 2-D URANS Approach

Interest in powered flight on Mars has been growing in recent years, and as such new developments are being made in determining the effects the Martian atmosphere has on the flow physics and performance, specifically with regards to similarity parameters: the Reynolds number & the Mach number. This paper aimed to investigate whether the...

Experimental Study of Shock Wave/Boundary-Layer Interactions over Fluttering Panels

Supersonic flows cause thin panels to flutter, which is characterized by high-amplitude self-sustained oscillations, increasing the risk of fatigue failure. Flutter is known to be exacerbated when a shock wave impinges on the panel, creating a shock wave/boundary-layer interaction (SWBLI) which promotes separation of flow and leads to increased...

Aerodynamic investigation of an airfoil in deep stall using SU2

Airfoils in deep stall have been a subject of extensive computational discussion in the past, with multiple efforts being performed by various institutions to test their solvers and turbulence/hybrid sub-grid scale (SGS) models for their use in massively separated flows. This case has an important application in turbomachinery where unsteady...

Noise radiation of a low Reynolds propeller at an angle of attack: an experimental and analytical study

This work presents an experimental and analytical investigation of unsteady loading of a low Reynolds number propeller and its relation to aeroacoustics. The propeller is positioned at an angle of attack with respect to the freestream which causes a variation in loading along the azimuth. The propeller is operated at 4000 RPM with an advance...

Aerodynamic Effects of the Flow Field in a Vehicle Rear Wheel Arch and its Effect on the Driving Resistance

The increasing importance of climate change and stricter regulations for greenhouse gas emissions raise the pressure on the automotive industry to develop more efficient products. Besides a reduction of emissions by new combustion engines, electric vehicles are being introduced to lower the fleet fuel economy. Especially this new drivetrain...

A sensitivity study on the aerodynamic performance of a wingtip-mounted tractor propeller-wing system

Wingtip-mounted propellers have the ability to enhance the propeller-wing system performance. For inboard-up rotating tractor propellers, the swirl in the propeller slipstream can be used on the wing to reduce the influence of the wingtip vortex, decreasing drag. Furthermore, lift is enhanced by increasing dynamic pressure and angle of attack...

Multi-Fidelity Aerodynamic and Aeroacoustic Sensitivity Study of Isolated Propellers

In the global search to more sustainable developments, research in the field of propeller propulsion systems is experiencing a renewed interest. The combination of efficiency and noise production is not studied as extensively as propeller efficiency alone in past studies. In this study, the relation between propeller noise and efficiency is...

Aerodynamic interaction effects of circular and square ducted propellers

With the goal of decreasing the environmental impact of aircraft, ducted propellers emerge as an efficient propulsive alternative. Ducts are able to increase the thrust to power ratio of a propeller system by both producing thrust and/or lowering tip losses of propellers. In this thesis, RANS CFD simulations were used to analyse the possible...

Unsteady Boundary Layer Transition Measurements with Infrared Thermography: Development of Improved Measurement Schemes

The boundary layer transition location is a crucial design parameter in aerodynamics. The computational prediction of boundary layer transition in engineering applications is typically based on empirical models. These models require experimental measurements for calibration and validation purposes. For unsteady aerodynamic processes, the range...

Investigation of the Effect of a Surface Protuberance on a High Speed Boundary Layer

One of the major challenges that engineers face when designing a high speed vehicle is aerodynamics heating. While ideally the external surfaces are expected to maintain a smooth profile, this is not the case in most vehicles, which might be laden with discontinuities like steps, gaps, and other protrusions. These could alter the local flow...

Mechanisms of boundary layer transition due to isolated roughness on swept wings: An experimental study

In the context of the ongoing research regarding boundary layer transition, this project aims to study the effects of isolated cylindrical roughness elements on the transition from laminar to turbulent flow in a swept wing boundary layer. The project entails experimental campaigns: the 45 degrees swept wing model is placed inside the test...