Air-water flow measurements were conducted in two large-size stepped chute facilities (θ = 3.4 & 16o) to study experimental distortion caused by scale effects and result extrapolation to prototypes. The stepped geometries corresponded to moderate slopes typical of embankment dams and storm waterways. Experimental data included distributions of air concentration, air-water flow velocity, bubble ...

New experiments were conducted in a large stepped channel with a 22o slope operating at large Reynolds numbers. Interactions between free-surface and cavity recirculation were systematically investigated in the skimming flow regime. Turbulence manipulation was further conducted and identical experiments were performed with 4 configurations. Basic results demonstrated a strong influence of cavit...

Air flow through electric fan heater channel is governed by coupled, non-linear partial differential equations; these equations have to be solved within on irregular domain subject to various initial and boundary conditions. Computational Fluid Dynamics (CFD) replaces fluid flow equations by a set of algebraic equations, these algebraic equations can be solved using digital computers. Wall to a...

Air turbulence is a serious problem that affects airline operations. The Japan Aerospace Exploration Agency (JAXA) is developing an airborne Doppler LIDAR (Light Detection and Ranging) for on-board turbulence detection. Flight experiments demonstrated that a highaltitude prototype can measure wind speeds at the more than 9 km range at altitude of 12 km. This paper describes the development of t...

The purpose of the study is to investigate the wind noise reduction provided by microphone windscreens at different frequencies of the impinging turbulence. The windscreen is assumed to be a cylindrically shaped porous medium. This paper uses a high-order scheme to improve the accuracy at the interface between air and porous medium. The computational scheme is based on a modified immersed-bound...

The effect of air turbulence on the geometric collision kernel of cloud droplets can be predicted if the effects of air turbulence on two kinematic pair statistics can be modeled. The first is the average radial relative velocity and the second is the radial distribution function (RDF). A survey of the literature shows that no theory is available for predicting the radial relative velocity of f...

Turbulence in the earth’s atmosphere severely limits the resolution and sensitivity of astronomical observations. The vertical distribution of turbulence in the atmosphere has a profound effect on the residuals after correction by an active instrument such as adaptive optics or a fringe tracking interferometer. It has already been shown that the South Pole has turbulence profiles unlike those a...

The flow and turbulence in an IC engine cylinder were studied using the SSG variant of the Reynolds stress turbulence closure model. In-cylinder turbulence is characterized by strong turbulence anisotropy and flow rotation, which aid in air-fuel mixing. It is argued that solving the differential transport equations for each turbulent stress tensor component, as implied by second-moment closures...

The objective of this research is to improve the surface flux and boundary layer turbulence parameterization in COAMPS for lowand high-wind events over the ocean in the context of air-sea interaction. Special emphasis will be placed on flux parameterizations in low-wind regimes in collaboration with CBLAST DRI (Coupled Boundary Layer Layers/Air-Sea Transfer Defense Research Initiative) community.

Clear-air Turbulence (CAT) is a significant safety issue for aviation at upper levels in the atmosphere. Since CAT is not observable with traditional remote sensing techniques, it is particularly difficult to avoid. The current FAA-sponsored CAT forecasting product, the Graphical Turbulence Guidance System (GTG), calculates many indicators or diagnostics of CAT potential from larger-scale numer...