Turbulence

How to fly a drone in turbulence? (MSc)

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Sketch of a drone flying in the WDY wind tunnel.

Measurements of atmospheric turbulence involve either the positioning of fixed probes on towers or flying probes mounted on airplanes. Here we want to investigate if drones could potentially be used as more flexible instruments to investigate atmospheric turbulence from inside the flow. Drones come in different sizes and, particularly the smaller ones, can be strongly affected by turbulent fluctuations, even at the smaller scales.

The question is whether we can use a small drone as a probe of atmospheric turbulence, for example by studying the signals of its accelerometers. The other question is how to design drone software so that it can cope more effectively with turbulence. We will use the TU/e wind tunnel which has a unique facility to generate "tailored" turbulence using a computer-controlled active grid.

In this project you will learn about the fundamental properties of turbulent flows, boundary layers, experimental techniques for fluid dynamics research, including the programming of active grids, the running of wind tunnels and …. drones flying.

Federico Toschi

Contact: Federico Toschi

 

Ventilation flow (BSc/MSc)

Ventilation flows are important for keeping a healthy indoor environment by removing for example pollutants in an efficient way. One way to enhance the ventilation efficiency of such flows is by making them time-dependent. Recent computational fluid dynamics (CFD) simulations suggest that the air exchange efficiency for an enclosure that is ventilated by a time-varying in- and outflow can be much higher than for a steady ventilation flow. The present project (Bachelor or Master) aims to better understand enhanced ventilation efficiency for time-dependent flows using concepts from dynamical system theory combined with two-dimensional direct numerical simulation (DNS) of incompressible flows in a rectangular  enclosure with an in- and an outflow opening.

Leon Kamp, GertJan van Heijst, Twan van Hooff (fac B)

Contact: Leon Kamp

 

Two-dimensional turbulence in bounded domain with sliding wall (MSc)

Numerical simulations on characteristics of two-dimensional turbulence in a compact domain with no-slip walls one of which is sliding. Spontaneous spin-up? Angular momentum reversals?

Leon Kamp, GertJan van Heijst

Contact: Leon Kamp

 

Convection under variable rotation (BSc/MSc)

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Image from numerical simulation displaying cold (blue) and hot (red) plumes gathering in a central column.

It is quite well-known that rotation affects the heat transfer between two plates at different temperatures, because the background rotation changes the nature of the turbulent flow. When the rotation speed Ω of the container is modulated, the flow and the heat transfer show a number of intriguing phenomena (like a growth and oscillating behavior of the Nusselt number, followed by a complete collapse) that are still not understood. Further numerical simulations and/or experiments are needed to unravel these phenomena.

Rudie Kunnen, GertJan van Heijst

Contact: Rudie Kunnen

 

Complex particles in complex flows (MSc/BSc)

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Instantaneous snapshot of the velocity magnitude with the corresponding particle position in homogeneous isotropic turbulence

The study of the transport of particles in turbulent flows have attracted significant interests in recent years. Yet many questions remain unanswered. We offer the possibility to investigate the dynamics of particles with simple or complex shapes, as well as with diverse physical properties, in turbulent flows. The student will employ in-house developed codes (Lattice Boltzmann and Pseudo Spectral) for the Direct Numerical Simulation (DNS) of turbulent flows with point-like and/or finite-size particles. The student analyse the statistical properties associated with particle dynamics, as well as the influence that particles exert on the fluid itself.

Federico Toschi

Contact: Federico Toschi

 

Visualising thermal convection using shaving cream (BSc)

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A tank of fluid heated from below and cooled from the top generates a convective flow, where plumes of hot fluid arise from the bottom and plumes of cold fluid fall from the top. Changing the temperature difference between the plates will generate different flow morphologies, ranging from laminar rolls to 3D turbulence. The flow features of this system have been widely investigated, making this problem, Rayleigh-Bénard convection, a staple of fluid dynamics. A new visualization technique, involving stearic acid contained in common shaving cream, will be tested and optimized in such a context.

Contact: Rudie Kunnen