In an open channel, a hydraulic jump is a sudden transition from a high-velocity to slower, fluvial flow motion. The impinging flow forms a turbulent roller with a highly fluctuating free-surface, while a large amount of air bubbles is entrapped at the jump toe. The present work presents some physical investigations of hydraulic jumps based upon a wide range of inflow Froude numbers (3.8 < Fr1 ...

In existing Cellular Automaton (CA) model, the cellular width is not related to vehicular velocity. However, in real condition, at road’s toll station or intersection, the introduced fixed infrastructure or pedestrians moving into vehicle lane will result in the lane narrowing, so limit the passing speed of vehicle. According to this condition, this paper presents a deformed CA model, and makes...

Convective heat transfer about an isothermal, cylindrical extrudate of constant diameter, issuing continuously from an extrusion die, is investigated numerically, using a commercial CFD software package. The hot extrudate is assumed to move vertically downward, thus giving rise to a combined regime of forced and free convection in the surrounding fluid. Prandtl number of 0.707, corresponding to...

High speed wind tunnels are widely used in the study of fluid flow behavior around various objects. The air flow in the starting step of supersonic wind tunnels is transient including strong shock waves caused by the interaction of the tunnel main stream and the boundary layer at walls. To arrive in running step, the tunnel must be designed so as these waves leave immediately the test section. ...

“Model-free” control and the related “intelligent” proportional-integral (PI) controllers are successfully applied to freeway ramp metering control. Implementing moreover the corresponding control strategy is straightforward. Numerical simulations on the other hand need the identification of quite complex quantities like the free flow speed and the critical density. This is achieved thanks to n...

Recent work in bio-fluid dynamics has studied the relation of fluid drag to flow speed for flexible organic structures, such as tree leaves, seaweed, and coral beds, and found a reduction in drag growth due to body reconfiguration with increasing flow speed. Our theoretical and experimental work isolates the role of elastic bending in this process. Using a flexible glass fiber wetted into a ver...

280 control on advanced, high-speed flight vehicles. Effective manipulation of a flow field using flow-control technologies can lead to a number of significant benefits to aerospace vehicle systems, including enhanced performance, maneuverability, payload, and range, as well as lowered overall cost. A research team led by APL is investigating the time-dependent fluid dynamic interactions betwee...

In design and analysis, standard references assume the pedestrian flow as unidirectional. In reality however, pedestrian flow is usually bi-directional. The main question pursued in this paper is that whether the main characteristics of pedestrian flow the same under uni- and bi-directional conditions. In order to achieve this goal, effect of bi-directional stream is inv...

The purpose of this study was to investigate traffic flow characteristics at off-ramp junctions in Iranian expressways. The study was conducted on the traffic behavior in isolated off-ramp vicinity of 6-lane expressways. The database consisted of traffic flow and traffic speed information extracted from videotapes. The relationship between diverging traffic flow in the right lane of expressway ...