Hydrogels have been attractive for use as a medium in porous flow studies,
but have always been limited in this role because of their poor mechanical properties.
This project analyzes and tests two recently developed hydrogels,
poly(methacrylamide-co-methacrylic acid) (PMM), and a heat-treated long chain
PVA hydrogel. Particle image velocimetry (PIV)...
The application of a flapping foil with prescribed trailing edge motion to energy harvesting in a low reduced frequency (k = fc/U∞) regime was experimentally studied. The effects of the phase and amplitude of the applied trailing edge motion upon time-variant power extraction capability have been measured and are interpreted....
The energy harvesting performance of oscillating airfoils is studied using a discrete vortex model (DVM) with a leading-edge separation criterion. The airfoil undergoes a combined sinusoidal heaving and pitching motion at reduced frequencies of k = 0.06 − 0.16, with heaving amplitude of h0 = 0.5c, and pitching amplitude of...
Oscillating foil energy harvesters are analyzed at optimal reduced frequencies (𝑘=𝑓𝑐/𝑈) to determine how the leading edge radius of curvature affects leading edge separation. The understanding of leading edge separation and its behaviors is critical to predicting the transient lift profile of an airfoil. The separation is therefore also critical...
An experimental setup has been partially developed to investigate the impact of an actively controlled trailing edge component upon the energy harvesting performance of an oscillating airfoil in a pitching and heaving regime. While previous and current efforts have and continue to
function to characterize the performance of such 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...
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...
There is a pressing need for Micro Air Vehicles (MAV) that are light, powerful, and efficient to perform military reconnaissance missions and search and rescue operations. These MAVs have length scales on the order of 10 cm, where traditional steady flight wing designs perform poorly. An alternative flight mechanism is...
The expansion of a gas within a piston-cylinder arrangement is studied in order to obtain a better understanding of the heat transfer which occurs during this process. While the situation of heat transfer during the expansion of a gas has received considerable attention, the process is still not very well...
Understanding the behavior of hydrophobic membranes is important for applications where separating a gas from a liquid-gas mixture is beneficial. For example, in-situ vapor extraction can be used in microscale heat sinks to improve heat transfer and flow stability. In this study, gas is experimentally evaluated flowing through flexible polytetrafluoroethylene...