Similarity Of Velocity Distribution Research Articles

不等流沿岸流における流速分布の相似性について

不等流沿岸流における流速分布の相似性について

Heat Transfer from a Flat Plate in Two-Component Mist Flow

An experimental study concerning the characteristics of heat transfer from a dry isothermal flat plate in two-component (water-air) mist flow has been performed for lower water-air mass flow ratios up to 2.3 percent. Heat transfer coefficients in mist flow increase several times corresponding to single phase coefficients with increasing mass flow ratio and free stream velocity, and with decreasing wall temperature. The measurements of droplet velocity employing laser Doppler anemometry indicate the similarity of velocity distributions in boundary layer of mist flow, which approximately fit the laminar single phase one. It is confirmed that an augmentation of heat transfer is attributable to a latent heat due to evaporation of water droplets within the boundary layer, and that, at a constant Reynolds number and wall temperature, the enhanced rates of heat transfer coefficients are linearly correlated to water mass flow rates for unit cross-sectional area.

Investigation of the velocity field in the space above the reactor bed for dehydrogenating ethylbenzene and butylenes

1. The velocity fields were measured in the volume above the bed of model reaction equipment, with fixed catalyst beds of diameters 100, 200, 250, and 600 mrm for all three designs of distributors. 2. It was found that similarity of velocity distribution is not maintained on increasing the model size. 3. Further investigation is necessary to determine the hydraulic modelling criteria for high-efficiency reactor and adsorption equipment.

Wake Distribution of Full Ships

This paper deals with the problem on flow fields around the stern of full ship forms and the estimation of ship wake from model data.The first part of the paper concerns the measurements of wake in full models and the discussions on the characteristics of flow fields. Wake and pressure were measured by Pitot tube rake and potential wake was separated by measuring wake in models towed astern. Flow observation by tufts was also carried out. Plateau-type distribution of wake and the existence of cross flow and two weak vortices at both sides of the propeller shaft seem to be main characteristics of flow fields in the stern of full forms. Discussion was made on the existence and the cause of cross flow.The seocond part is on the extrapolation of model wake to full sized ships. Assuming linear superposition of frictional and potential wakes and also similarity of velocity distribution in frictional wake between models and ships, an estimation of ship wake was attempted from the measured model data. Some secondary corrections such as the variation of potential wake between models and ships due to the difference of viscous displacement effect were also considered. Results were shown in the form of wake contours. A comparison of wake shows good agreement between the estimated value and the one obtained from the ship trial analysis.