Improving rowing performance by adjusting oar blade size and angle

A 1:5 scaled rowing boat had been designed by a previous research group to determine the performance of rowing blades with different sizes and blade angles. In this research modifications were done to allow more control of the rowing motion. The aim of this study is to assess whether an angled oar blade can reach faster speeds with the same...

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...

Exploratory research on application Multi-Level Multi-Fidelity Monte Carlo in fluid dynamics topics: study on flow past a porous cylinder

In offshore engineering complex simulation models are constructed for design optimization using Monte Carlo methods. These models incur large computational costs. Multi-Level Multi-Fidelity Monte Carlo is proposed as a method to reduce the computational cost of these simulations. In addition, research is conducted on the use of porous media as...

Experimental investigation of cavitation-induced erosion around a surface-mounted bluff body

The objective of this study is to investigate the collapsing behavior of cavitation, which leads to the erosion of material. An experimental examination was conducted in a channel with a semi-circular cylinder obstacle, which serves as a “vortex cavity” generator. Cavitation was achieved by employing a range of pressure differences over the...

Hydrodynamics of rowing propulsion

This paper presents the results of the time resolved flow field measurements around a realistic rowing oar blade that moves along a realistic path through water. To the authors' knowledge no prior account of this complex flow field has been given. Simultaneously with the flow field measurements, the hydrodynamic forces acting on the blade...

Modelling vortex-induced vibrations with a single wake oscillator coupled to both cross-flow and in-line motions

Vortex-induced vibration or as well-known as VIV is a phenomenon that has caught the attention of engineers along history. VIV is related to many engineering fields. In the offshore industry, it is of importance for risers that extract oil from the subsoil, and tethered anchors for floating units.<br/>The main aim of the thesis is to model the...

Experimental study of cavitation erosion around a surface mounted semi circular cylinder

The objective of this study is to investigate the collapsing behavior of cavitation, which leads to erosion. For this purpose, an experimental investigation was performed in a channel with a semi-circular cylinder obstacle at the Hydraulic Laboratory of ANDRITZ HYDRO in Vevey. Cavitation was achieved by employing a range of pressure differences...

Spectral analysis of New MEXICO standstill measurements to investigate vortex shedding in deep stall

Spectral analysis was performed on the time series data computed from pressure measurements on the New MEXICO (Model Rotor Experiments under Controlled Conditions) rotor in standstill conditions. As a priori, 3D airfoil polars were recreated from standstill measurements and compared against 2D airfoil polars and flat plate theory results to...

Drag force on an accelerating submerged plate

We present results on the drag on, and the flow field around, a submerged rectangular normal flat plate, which is uniformly accelerated to a constant target velocity along a straight path. The plate aspect ratio is chosen to be to resemble an oar blade in (competitive) rowing, the sport which inspired this study. The plate depth, i.e. the...

Dynamic Stall Modeling for Wind Turbines

Modern wind turbines frequently operate at off-design conditions during their life cycle. They undergo dynamic loads characterized by unsteady aerodynamics. Predicting these unsteady aerodynamic loads has been very difficult due to the non-linear nature of unsteady aerodynamics. Especially when operating near the stall region, these turbine are...

Experimental investigation of aerofoil tonal noise generation

The present study investigates the mechanisms associated with tonal noise emission from a NACA 0012 aerofoil at moderate incidence (0; 1; 2 and 4 angle of attack) and with Reynolds numbers ranging from 100 000 to 270 000. Simultaneous time-resolved particle image velocimetry (PIV) of the aeroacoustic source region near the trailing edge and...

Vortical Structures and Turbulent Bursts Behind Magnetic Obstacles in Transitional Flow Regimes

The present paper reports on numerical investigations of vortical structures in transient flow regimes generated by the local action of the Lorentz force on an electrically conductive fluid. The locally imposed non-uniform magnetic field generates similar effects as observed for flows over submerged solid obstacles. It is demonstrated that...

A study of grid convergence issues for the simulation of the massively separated flow around a stalled airfoil using DES and related methods

A systematic grid convergence study is conducted for the Detached-Eddy Simulation (DES) of the massively separated flow around a NACA0021 airfoil at high angle of attack. In order to study the convergence characteristics of DES/LES problems, velocity fields using a series of grids must be generated that demonstrate sufficient dynamic similarity...

Numerical study of turbulent flow around a square cylinder using low-Reynolds-number k-e model

This paper discusses the abilities of two different low-Reynolds-number eddy-viscosity models in resolving the complex physical features that arises in turbulent flows around a square cylinder at Re=22000. For the modeling of turbulence, the Launder & Sharma (LS) [1] and Kawamura & Kawashima (KK) [2] low-Re models have been employed. The present...

Simulation of unsteady flow past tapered circular cylinders using an immersed boundary method

Three-dimensional numerical calculations of laminar vortex shedding behind a linearly tapered circular cylinder with taper ratio 75:1 have been carried out at a Reynolds number 131 (based on the large diameter and the uniform inflow velocity) using a Finite Volume code. Computations were performed on a staggered-Cartesian grid and a direct...

Large eddy simulation of 3D turbulent flow around deep-sea marina structure

The purpose of this paper is to investigate the highly complex interaction between turbulent flow and deep-sea marina structure using a commercial CFD code (FLUENT 6.2) with Large Eddy Simulation (LES) approach. A series of three-dimensional LES of wake flows past overlapping cylinder of finite height are carried out with a range of Reynolds...

On wings and keels

A discussion is given of the physical mechanisms governing the hydrodynamics of sailing yacht keels and the parameters that, through these mechanisms, determine keel performance. It is concluded that due to the presence of the free water surface optimum keel shapes differ from optimum shapes for aircraft wings, a fact that does not seem to have...