Spelling suggestions: "subject:"shock (mechanics) -- 1ieasurement"" "subject:"shock (mechanics) -- remeasurement""
1 |
Set-up and evaluation of laser-driven miniflyer systemMiller, Christopher W. 08 April 2009 (has links)
A laser-driven miniflyer system is built in design similar to those at the Los Alamos National Laboratory and Eglin Air Force Base. It is composed of three parts: laser drive source, impact experiment assembly, and diagnostics. The laser drive source is a Nd:YAG laser operating at 1064nm at a maximum energy of 3 J. The impact experiment assembly consists of a BK7 substrate on to which is deposited an ablation layer consisting of carbon, alumina, and aluminum. Mounted on the ablation layer is a metal foil (flyer). The carbon in the ablation layer absorbs the laser energy to form a rapidly expanding plasma. The alumina and aluminum layers provide thermal insulation and also contain the plasma. The set-up is expected to provide flyer velocities in the range of 100 to 1000 m/s. Diagnostics consist of a Photonic Doppler Velocimetry (PDV) system that uses Doppler-shifted coherent laser light to measure the instantaneous velocity of a moving surface, as well as velocity dispersions caused by mechanical or material heterogeneities. This thesis will provide a description of the set-up of the laser-driven miniflyer system, as well as an evaluation of the flyer velocity, measured using the PDV system, as a function of laser energy. The flyer velocity trends will be used in order to characterize and calibrate the system. A manual providing system operation instructions will also be included to serve future users of this miniflyer system
|
2 |
Development of a new shock capturing formula for pressure correction methodsGupta, Ajay K. 17 December 2008 (has links)
Several methods have been developed to capture shock waves in turbo machinery flows, such as Moore's pressure correction procedure and Denton's time marching procedure. The time marching procedure is traditionally used for transonic flow calculations, whereas the pressure correction method is better suited for incompressible and subsonic flows. However, the focus of this research is on the Moore pressure correction flow code, the Moore Elliptical Flow Program (MEFP) , to calculate shock waves in transonic compressor fans.
A new pressure interpolation method, the 2M formula, is developed to improve the shock capturing capabilities of the MEFP flow code. The 2M formula is a two Mach number dependent formula, with Mach numbers Mi and M i + 1. The previously used pressure interpolation method, the M&M formula, is a one Mach number dependent formula, using the maximum of Mi and Mi + 1 . In the development of the 2M formula, J.G. Moore's stability criterion is applied to the pressure correction equation such that the center point coefficient is greater than the sum of the other positive coefficients. / Master of Science
|
Page generated in 0.1006 seconds