583 research outputs found
New calculation scheme for compressible Euler equation
In this paper, numerical demonstrations of a modified compressible Euler system are shown, where the bubble function element stabilization method together with adaptive mesh refinement is introduced for increasing numerical stability and numerical accuracy. For a test case, NACA0012 is selected as a domain of interest, and numerical results using finite elements of P1­P1b­P1 and P2­P2b­P2 for density­velocity­pressure were compared at AOA=1.25 and Mach number 0.8. As a result, the shock wave is not found on the upper­end and the lower­ end of NACA0012 in the former, and on the other hand the latter is adequate numerical result and relative errors of Cl, Cd with previous study are 1.197% and 0.15376%. The mathematical model is much simpler than the compressible Euler equation, because they are advection equations for a density, a velocity, and a pressure with each external forces. Therefore, the material derivative is considered for time stepping, and the characteristic curve method can be used for decreasing calculation cost
Investigation of the Coefficient of Earth Pressure for Improved Ground by Compaction Grouting in the Full-Scale Field Liquefaction Experiment
This paper describes the effect of countermeasures for liquefaction by compaction grouting, which was investigated by the experiment of full-scale field liquefaction by controlled blast technique. The experiment was conducted to assess the performance of airport facilities subjected to liquefaction, to investigate damage mechanism, and to estimate the effect of countermeasures for liquefaction by compaction grouting applied to liquefiable sand layer under runway pavement. In this study, before and after grouting and after artificial liquefaction caused by in-situ blasting, self boring pressure-meter tests at the center and the edge of a grouted area were carried out to investigate the coefficient of earth pressure, K, for evaluation of the improved ground because it is generally known that compaction grouting makes K-value increase in and around the grouted area. Additionally, to estimate the continuation of improving effect after liquefaction, K-values after blast were also investigated at same points. As the results of investigation, it was found that post-liquefaction K-value was higher than that of untreated ground before improvement and compaction grouting with cost-reduction design examined in this study, that is, the cost-reduction design is effective
Development of a low-alpha-emitting {\mu}-PIC for NEWAGE direction-sensitive dark-matter search
NEWAGE is a direction-sensitive dark-matter-search experiment that uses a
micro-patterned gaseous detector, or {\mu}-PIC, as the readout. The main
background sources are {\alpha}-rays from radioactive contaminants in the
{\mu}-PIC. We have therefore developed a low-alpha-emitting {\mu}-PICs and
measured its performances. We measured the surface {\alpha}-ray emission rate
of the {\mu}-PIC in the Kamioka mine using a surface {\alpha}-ray counter based
on a micro TPC.Comment: 6 pages, 4 figure
- …