A time domain simulation model which approximates the
three-dimensional velocity fluctuations of wind turbulence
has been developed. This model is used in a discrete time
control algorithm to regulate the output torque of a wind
turbine by changing the pitch angle of the turbine blade.
The wind model provides a...
Vortical structures are the driving mechanism of transition to turbulence in porous media requiring adequately resolved observations along with analysis of the scale and energy of flow within the pores. Of specific interest is to understand the vortex dynamics, energy, and turbulent mixing and transport properties in the scale of...
Treatment of extrahepatic portosystemic shunts provides many options, including cellophane banding. These cellophane bands are secured with a ligation clip. Weck® offers two forms of these: the stainless steel Hemoclip, and the polymer Hem-o-lok. This in vitro study compares the mechanical strength of these two of types of clips by...
Several wave energy converter designs have been recently proposed that are made of flexible materials. Flexible devices are able to generate electricity by being stretched, and are intended to simplify deployment and maintenance concerns over existing wave energy devices. Due to the relative infancy of flexible wave energy converters, however,...
Modern engineered systems are increasingly integrated into society, decentralized, and interconnected. However, scale and complexity create unique challenges in system design, such as emergent behavior and unintended consequences. This work investigates the structural characteristics of robustness in complex engineered systems by identifying patterns of under-recognized vulnerabilities at various levels of...
The aerodynamic performance of an oscillating pitching and plunging foil operating in the energy harvesting mode is investigated. Experiments are conducted in a closed-loop recirculating wind tunnel at Reynolds numbers of 24,000 to 48,000, and reduced frequencies (k = fc/u) of 0.042 to 0.083. Foil kinematics are varied through the...
Porous media are the materials containing void space or pores, where fluids and gases can pass through. Unsteady flows in porous media are encountered in many engineering applications and natural problems, such as CO₂ sequestration, high temperature nuclear reactor cooling, high efficiency combustion, chemical reactors, noise reduction on airplane trailing...
Particle-laden turbulent flows, wherein a large number of small size particles are dispersed in a fluid, are widely encountered in environmental and industrial applications. Understanding their underlying physics, making predictions without performing expensive experiments, and ultimately optimizing the systems carrying such flows, require accurate and robust modelling tools. The Euler-Lagrange...
The rising global trend to reduce dependence on fossil fuels has provided significant motivation toward the development of alternative energy conversion methods and new technologies to improve their efficiency. Recently, oscillating energy harvesters have shown promise as highly efficient and scalable turbines, which can be implemented in areas where traditional...
It is desirable for complex engineered systems to perform missions efficiently and economically, even when these missions' complex, variable, long-term operational profiles make it likely for hazards to arise. It is thus important to design these systems to be resilient so that they will actively prevent and recover from hazards...