this paper is an attempt to numerical modeling and experimental study of air flow in the yazdi wind-towers. wind towers has been known as one of the most effective climatic elements in iranian traditional architecture. this paper is an attempt to evaluating yazdi wind-tower to discussion the two main questions: 1. what is the role of orientation of wind-towers span, regarding to climate and hei...

A large eddy simulation (LES) program with the Smagorinsky subgrid-scale model has been used to study cross natural ventilation in buildings, which has experimental data available from on-site measurements and a wind tunnel. Since natural wind changes direction over time, it is hard to reproduce this effect in a conventional wind tunnel where the “wind” direction is fixed. There are discrepanci...

This paper discusses the possibilities of laboratory simulation of large-scale flow around dunes, both with and without saltation, and the study of the physics of the small-scale particle motion occurring on a sand surface composed of like-moveable particles. Physics of the atmospheric boundary layer are presented in the context of laboratory applications. The governing equations of fluid and/o...

in this article, an algorithm for designing of a supersonic wind tunnel injection nozzle ejector is presented and based on this algorithm, a new ejector is designed for a supersonic wind tunnel. the injection nozzle consists of a volute, a nozzle, and several vanes. designed injection nozzle is simulated numerically, and the results are compared with the present injection nozzle. the results sh...

The effect of skis on the force-time characteristics of the simulated ski jumping takeoff was examined in a wind tunnel. Takeoff forces were recorded with a force plate installed under the tunnel floor. Signals from the front and rear parts of the force plate were collected separately to examine the anteroposterior balance of the jumpers during the takeoff. Two ski jumpers performed simulated t...

Viscous effect of wing in ground effect in wind tunnel test was investigated numerically. Ground settings in wind tunnel test were simulated by specifying different ground boundary conditions in CFD. It was revealed for fixed-ground based wind tunnel test that: boundary layer developed from the ground deforms effective ground surface and introduces a decreased effective ground clearance; a shar...

Despite the fact that the wind tunnel tests have been carried out on iced transmission lines subjected to wind load, it is not practical to do wind tunnel tests due to its high cost. This paper describes a detailed numerical simulation method that can be used to instead of wind tunnel tests. Based on the galloping mechanism of iced transmission lines, the aerodynamic test was simulated with the...

A model of the atmospheric convective boundary layer (CBL) is realized in the thermally stratified wind tunnel of the Institute of Hydrology and Water Resources, University of Karlsruhe. Further experimental results from this model are presented. The wind tunnel with a test section 10 m long, 1.5 m wide, and 1.5 m high allows one to generate a quasi-stationary, horizontally evolving CBL, charac...

A micro aerial vehicle with a variable forward-sweep wing is proposed with the goal of enhancing performance and controllability during high-angle-of-attack perching maneuvers. Data is presented from a series of wind tunnel experiments to quantify the aerodynamic effects of forward sweep over a range of angles of attack from -25° to +75°. A nonlinear dynamics model is constructed using the wind...

A study of steady lift interference effects in wind tunnels with several different wall conditions has been carried out using a three-dimensional resistance network. The methods by which the various boundary conditions were simulated on the network are described in detail; conditions included closed, open, slotted and perforated walls. The evaluation of interference parameters is described, and...