Development of scaling methods for broadband turbulent noise in internal flow devices by means of experiments and CFD

Broadband turbulent noise can lead to fluid-acoustic and fluid-structure interaction and ultimately to mechanical failure of pipe systems. In HVAC (Heating Ventilating and Air Conditioning) systems broadband turbulent noise can radiate outwards where it is a nuisance or even harmful to people. A fast and simple approach for investigating...

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...

Foamer evaluation by the sparging test method for application to gas well deliquification

Natural gas wells produce small amount of liquids along with the gas. During the initial part of the reservoir life, the gas velocity in the well tubing is large enough to drag the liquid upwards. As the well matures, the reservoir pressure starts to decline leading to a decline in the gas velocity in the tubing; here the gas momentum is not...

Failure criteria for evaluating Strength of Adhesive joints

An attempt is made to evaluate all possible stress based failure criteria that have been otherwise traditionally used for ductile metals and also some other criteria popularly used for polymers. In additional some other intuitive criteria were also derived.

Bio-inspired locomotion of a rotating cylinder pair

We developed bio-inspired reduced-order models of swimmers, consisting of a self-propelling pair of rotating cylinders. The aim of the project is twofold. First, simplified and non-deforming geometries can more easily be employed in small-scale robotic applications to solve relevant engineering problems. Second, they can serve as reduced physics...

Signatures of Chaos: A study in predictability of flows

This work explores predictability in atmospheric flows. A study on forecasting is conducted in the Lorenz [1963] model using several Data Assimilation techniques. Methods of statistically combining model forecasts with observations for prediction are tested for their performance, which readily extend to higher dimensional systems and are oft...

Universal aspects of small-scale motions in non-equilibrium turbulent channel flow

Direct numerical simulations of transient turbulent channel flow were conducted in order to study and characterize the large-small scale interaction in this type of flows. This was achieved by analyzing some well-known universal aspects of turbulence. Additionally, the so called strain-rate-eigenframe analysis was applied to study the local flow...

Investigating Step Cylinder Wake Topology with Tomographic PIV

Step cylinders have numerous applications, for instance, radio communication towers, airport control-towers, antenna members, etc. Numerous applications motivate researchers to investigate this bluff body both numerically and experimentally. The single step cylinder model is comprised of a small-diameter cylinder (d) attached coaxially to a...

Self-Sustaining Mechanisms in Wall Bounded Turbulence: Merging & auto-generation of vortices

For channel flow, we explore how a hairpin eddy may reach a threshold strength required to produce additional hairpins by means of auto-generation. This is done by studying the evolution of two eddies with different initial strengths (but both below the threshold strength), initial sizes and initial stream-wise spacing between them. The...

Transition to turbulence in Taylor Couette flow

The most recent studies of intermittent state in linearly stable shear flows, like pipe, Plane Couette and Taylor Couette flow, have shown that turbulent structures, created by finite-amplitude perturbation, have an exponential distribution of the lifetimes. Here we experimentally examine the lifetime of turbulent spot in Taylor Couette flow ...