The interest in aerodynamic heating problems has been increasing rapidly in the last decade. This interest is no longer concentrated on the heating of simple shapes for which adequate heat transfer theory has been developed« Because of the increasing Mach number ranges of aircraft, the need for information on the aerodynamic heating of various components has become imperative. Only when the magnitude of the problem has been exposed can the design for reducing the severity of local heating be optimized. Definition of these problems is of interest, not only because of the flow phenomena, but because of possible design limitations of re-entry vehicles and supersonic aircraft inlets, wings, rudders, etc.

Heat transfer study on gas turbine blades is very important due to the resultant increase in cycle thermal efficiency. This study is focused on the heat transfer effects on a reference nozzle guide vane and test rig component preparation in heat and power technology division at KTH. In order to prepare the current test rig for heat transfer experiments, some feature should be changed in the current layout to give a nearly instant temperature rise for heat transfer measurement. The heater mesh component is the main component to be added to the current test rig. Some preliminary design parameters were set and the necessary power for the heater mesh to achieve required step temperature rise was calculated. For the next step, it is needed to estimate the heat transfer coefficient and the other parameters for study on the reference blade using numerical methods. Boundary layer analysis is very important in heat transfer modeling so to model the reference blade heat transfer and boundary layer properties, a 2D boundary layer code TEXSTAN is used and the velocity distribution around the vane was set to an input dataset file. After elements refinement to ensure the numerical accuracy of TEXSTAN code, various turbulence modeling was check to predict the heat transfer coefficient and boundary layer assessments. It was concluded from TEXTAN calculations that both suction and pressure side have transition flow while for the suction side it was predicted that the flow regime at trailing edge is fully turbulent. Based on the Abu-Ghannam –Shaw Transition model and by the aid of shape factor data, momentum Reynolds number and various boundary layer properties, it was concluded that the pressure side remains in transient region.

The rise of soft robots poses a promising revolution across a variety of fields, such as invasive surgical procedures or aquatic animal monitoring and sampling, by providing a softer solution to delicate problems. However, with their youth comes a need for growth, particularly in regard to increasing mobility in aquatic environments seeing as motion is often slow and belabored. Additionally, exit strategies in breaking the air-water interface are not thoroughly explored to date. To address these challenges, this study looks to bioinspiration for the answer in the form of Emperor Penguins. By utilizing microbubbles in their plumage to decrease drag forces on their bodies, Emperor Penguins are able to propel themselves out of the water to heights not theoretically achievable through buoyancy alone. Not only is the strategy highly effective, it lends well to the soft robotic field as pneumatic actuation is a commonly used mechanism of locomotion. To explore this behavior and simulate its effects, this study tests a hollow silicone ellipsoid with hole punctures applied to its surface for microbubble release. Bubble characteristics such as separation point, bubble diameter, and downstream bubble expansion were monitored when subjected to a fluid flow to determine ideal air pressure through the ellipsoid body. Drag reduction is tested by measuring the robot’s leap height out of the water.

<div>Wind-tunnel experiments with a sharp 7-degree half-angle cone and a 33% scale Boundary Layer Transition (BOLT) model were performed in the Boeing/AFOSR Mach 6 Quiet Tunnel to investigate the effects of forward- and backward-facing steps on boundary-layer instability and transition. Each model was modified to include intentional steps just downstream of the nosetip. Experiments were performed at different freestream Reynolds numbers and varying step sizes. Infrared thermography was used to calculate surface heat transfer, and high-frequency pressure sensors were used to measure pressure fluctuations. A replica measurement technique was used to accurately measure step heights on the BOLT flight vehicle and the wind tunnel model.</div><div><br></div><div>A 7-degree half-angle cone was tested at 0-degree and 6-degree angles of attack. Step heights ranged from 0.610 mm to 1.219 mm. At a 0-degree angle of attack, no significant increases in heat transfer were observed with any of the forward- or backward-facing steps. However, a 250 kHz instability was measured with the forward-facing steps. Growth of the instability was similar to a second-mode. At a 6-degree angle of attack, an increase in heat transfer was observed on the windward ray with the forward-facing steps. Sharp increases in heating rates and increased pressure fluctuations were indications of boundary-layer transition. Elevated heating rates and pressure fluctuations were not measured with the backward-facing steps.</div><div><br></div><div>The BOLT model was tested at 0-degree, 2-degree, and 4-degree angles of attack and 2-degree and 4-degree yaw angles. Step heights ranged from 0.076 mm to 1.016 mm. At a 0-degree angle of attack and 0-degree yaw angle, thin wedges of heating were observed with the backward-facing steps. Instabilities were measured near these wedges of heating and are thought to be caused by a secondary instability. The effects of the steps were magnified on the windward side of the BOLT model at angles of attack. Wedges of heating were wider and more intense. At higher angles of attack, the onset of heating was further upstream. Sensors near and directly underneath the wedges of heating measured pressure fluctuations that were indicative of a turbulent flow. Wedges of heating were also observed at a 4-degree yaw angle, but only with the 1.016 mm backward-facing step.</div>

This work is aimed at investigating diurnal cycle variability of the planetary boundary layer characteristics over the Arabian Peninsula and the Red Sea region. To fulfill this goal the downscaling simulations are performed using Weather Research and Forecasting (WRF) model. We analyze planetary boundary layer height, latent and sensible heat fluxes, and surface air temperature. The model results are compared with observations in different areas, for different seasons, and for different model resolutions. The model results are analyzed in order to better quantify the diurnal cycle variability over the Arabian Peninsula and the Red Sea. The specific features of this region are investigated and discussed.

A turbulent boundary layer (TBL), generated in a water tunnel, extended to a highly turbulent and anisotropic “free stream” that consisted of a uniformly sheared flow (USF) with a mean shear that was in the opposite direction to that in the TBL. Extensive measurements of the fluctuating velocity were taken with the use of hot-film anemometry, laser Doppler velocimetry and particle image velocimetry. On either side of the TBL edge, defined as the location of maximum velocity, the turbulence relaxed to its canonical structures in TBL and USF, respectively, but, in the vicinity of the edge, the turbulence was multi-structure and exhibited strong departures from canonical behaviour. Of particular interest was the variation of the dissipation parameter, which, in contrast to its near-constancy in well-developed canonical flows, varied inversely proportionally to the turbulence Reynolds number. The entire flow contained horseshoe-shaped coherent structures, whose properties, however, varied from the TBL, across the multi-structure region and into the USF.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology, 1978. / Microfiche copy available in Archives and Science. / Bibliography : leaves 116-119. / by David William Heinold. / M.S.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Meteorology, 1969. / Vita. / Bibliography: leaves 56-57. / by Albert W. Green, Jr. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 211-213. / by Si, Boon-Ing. / M.S.

Thesis. 1977. Sc.D.--Massachusetts Institute of Technology. Dept. of Meteorology. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND LINDGREN. / Vita. / Bibliography : leaves 136-139. / Sc.D.