Assessment of nasal airflow simulations: On the accuracy and usage of CFD simulations for healthy and NAO patients

Nasal airway obstruction (NAO) is one of the most common symptoms in the human respiratory system and causes a considerable financial burden to both individuals and society. Currently, NAO detection is troublesome to achieve, which can influence the accuracy and effectiveness of clinical surgery. Although several objective measurement techniques...

Turbulence Decay of a Shear-Thinning Fluid in Pipe Flow: A DNS Study

The human body is the subject of several interesting phenomena and blood flow comes under that category. The main motivator for this thesis is the flow of blood in aneurysms. An aneurysm is a sudden expansion of an artery, with large expansion angles causing an adverse pressure gradient and leading to flow separation. Several studies have shown...

Experimental investigation of influence of an air cavity on a turbulent boundary layer using PIV

The turbulent boundary layer development under the influence of an air cavity is studied experimentally using planar PIV, with the aim of gaining insight and building upon the flow physics typically encountered in the application of air layer drag reduction. A detection technique based on correlation values is implemented to obtain an...

Transition to turbulence in particle-laden pipe flows

Multiphase flows are found in abundant natural phenomena and industrial processes. In particular, pipe flows are widely popular in industries involving chemical processing, dredging, and oil transport to name a few. Particle laden flows are often observed in applications like dredging, sediment, and slurry transport through pipes, etc. Therefore...

Path Instabilities of a Rising or Falling Sphere in a Fluid at Rest: An Experimental Study

Multi-phase flows are ubiquitous in nature and in everyday life surrounding us, impacting us in almost all possible ways. The presence of particles in a flow can change the flow behaviour in an unpredictable manner. The simplest example of a particle-laden flow, that one can think of, is the settling of a single sphere under gravity in a...

Indirect estimation of mean vorticity from polarized emission of nanoparticles in turbulent duct flows

Optical measurement techniques are widely used in fluid mechanics to measure quantities like velocity, vorticity, and temperature. They are usually non-intrusive visualization techniques that provide a major advantage by not influencing the flow properties. Most of the developed measurement techniques estimate vorticity by computing the...

Small scale testing of crawler outlet diffusers for plume reduction of offshore mining

Over recent years, there has been an increase in demands for rare and precious minerals worldwide. Mostly this is due to the rise of the world’s population and the drive towards a green energy transition and low carbon economy. Prices are rapidly increasing, and there is an identifiable risk of an increasing supply shortage of raw materials,...

Optimisation of Flow Distribution for Pipe Pullback in Horizontal Directional Drilling

Horizontal Directional Drilling permits the creation of tunnels which pass beneath rivers and canals to allow the passing of services from one side to the other. The final stage of this process involves lining the tunnel with a plastic or steel pipe. The pipe is pulled inside into the borehole using the same drilling rig that was used to bore...

Numerical analysis of blood flow patterns in simplified aortic root with prescribed valve kinematics

The aortic valve is a valve made of three thin flexible leaflets which open and close in order to allow the unidirectional passage of blood from the left ventricle to the aorta. Because of this repetitive motion at each cycle, the valve is constantly exposed to large variations of pressure and hemodynamic forces. Deterioration in its peculiar...

Cavitation: Experimental investigation of cavitation regimes in a coverging-diverging nozzle

Study of tin droplet impact on substrate at low pressure using particle tracking Velocimetry

The influence of free-surface turbulence on scum-layer formation

Droplet behaviour in a cavity mixing-layer

The transport of a dry gas through corrugated pipes can lead to flow-induced pulsations, which can result in tonal noise production and fatigue failure of the pipe or coupling. The unwanted effect can be prevented by increasing the liquid content. The effect of liquid on the one flow-induced pulsations is yet unknown, but one of the proposed...

The Effect of Pre-Rotation on Pump Performance

The aim of this thesis is to study the effect of pre-rotation on the performance of an axial flow pump manufactured by Xylem Flyght. Through theory and experiments, it is known that pre-rotation or swirl in the flow is an adverse effect, as it reduces the efficiency of the pump system. But the extent of this effect cannot be predicted to good...

CFD Modeling of Abdominal Aortic Aneurysms

An abdominal aortic aneurysm (AAA) is an excessive localized swelling of the abdominal aortic wall. AAAs are often lethal when they rupture and constitute a significant health risk in the developed countries. CFD simulations can help predict formation, progression, and rupture of AAAs by the use of hemodynamic parameters such as the Oscillatory...

Oblique Particle-Wall Collisions in a Viscous Fluid

Interaction of particles in a viscous fluid with a wall and with other particles is often observed in phenomena like sedimentation, erosion and filtration processes. With the increasing computational power there is now the possibility of simulating such particle-laden flows from a micro-scale perspective by direct application of no-slip/no...

Flow over a partially liquid filled cavity

Tonal noise and mechanical vibrations appear in flexible risers by throughput of dry gas flow. In this master thesis the effect of adding liquid to the fluid stream in the flexible risers is investigated, as this would possibly reduce the tonal noise and mechanical vibrations. Since flexible risers are a concatenation of cavity-like structures,...

Phase resolved PIV analysis of an undulating fin: Experimental investigation of the Galatea propulsion mechanism

In the world of underwater measurements and inspections there is a large demand for autonomous underwater vehicles(AUV) to decrease the cost and dangers involved in such operations. Small and low cost AUV can operate in many fields including hydrography, marine geology, coastal engineering and marine biology (habitat mapping). A concrete example...