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Fundamental Principles of Aerodynamics (Subsonic)
Published in Rose G. Davies, Aerodynamics Principles for Air Transport Pilots, 2020
The Venturi effect is the fact that reduction of static pressure fluid is caused by decreasing the cross-section area of the flow path. Examples of the Venturi effect are shown in Figure 2.3: (a) the airflow between two moving aircraft; (b) Venturi tube; and (c) carburetor of a petrol engine.
Tidal and Wave Power
Published in Bella H. Chudnovsky, Transmission, Distribution, and Renewable Energy Generation Power Equipment, 2017
Venturi-based turbine: These turbines have a horizontal axis, but they present a venturi-shaped duct, whose function is to accelerate the water stream and consequently, increasing the power extracted for a determined value of the radius of the rotor (Figure 10.4). The venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section (or choke) of a pipe. The venturi effect is named after an Italian physicist Giovanni Battista Venturi (1746–1822).
A distinctive determination of circular nozzles in downcomer for column flotation
Published in Particulate Science and Technology, 2023
Hüseyin Vapur, Soner Top, Mahmut Altiner
The optimum collector and frother for recovery of HCT using Yates test technique were determined as diesel oil and MIBC, respectively. Then, JC tests were performed using Box Behnken test design for new type of circular nozzles. The use of lower-diameter circular nozzles created a venturi effect of air current and a negative vacuum leading to a reduction in fluid pressure and an increase in fluid velocity. By using circular nozzle of 5 mm, a higher amount of cleaner coal was obtained with JC compared to conventional Denver flotation cell. This indicated the increased CC. The average CRs (%) were over 95% as a good effect of the cell design. The average calorific values of the concentrates were 6,550 ± 100 kcal/kg. The fixed Carbon ratio was found to be 54.55% according to ASTM standards (Table 7). This study showed that the clean coal with high recovery ratios and low ash rates could be separated from the HCT using proper nozzle diameter. Therefore, a qualified concentrate with suitable CC could be recycled. The product can be used for coke and semi-coke processes for blast furnace industry as a qualified fuel source and this process can provide prevention of air pollution with a low sulfur content (0.38%).
Study of the influence of input parameters in an air channel on mass and heat transfer phenomena within a wall saturated with water: application to the renovation of old wet buildings
Published in Journal of Building Performance Simulation, 2022
W. Ghrissi, G. Promis, T. Langlet, O. Douzane, R. Chouikh, A. Guizani
This section focuses the analyse of the air speed at the entrance of the cavity on the distributions of temperature and moisture. The air speed field lines in the channel are illustrated in Figure 15, in the case where the blown air speed reaches . Firstly, streamlines are uniform, confirming a laminar flow. Near the both side of the channel (the wall and the plate), the streamlines become closer due to the interaction with the rough surfaces on each side of the channel leading to the change of fluid velocity. Indeed, at the entrance of the channel the air speed is braked by frictional forces and pressure. Those forces, acting in the opposite direction of the air flow, slow it down. The deceleration of the flow near the walls is compensated by an acceleration at the level of the median plane of the channel, in order to satisfy the mass conservation equation. Thus, from mid-height of the channel and the achievement of a steady state, the axial air velocity profile becomes more convex, taking a parabolic shape in the axis of the channel. The air speed increases by 1.3 times the initial speed and becomes equal to . The pressure exerted by the wall and the plate from each side of the channel decreases when the fluid velocity increases, governing by the Venturi effect.
A simplified model for drag evaluation of a streamlined body with leading-edge damage
Published in Journal of Turbulence, 2021
Haoliang Yu, Umberto Ciri, Arif Malik, Stefano Leonardi
Regarding the velocity field around the bump, in both the smooth and uniform step cases, on the windward side the flow is subjected to an FPG which leads to an increase in velocity and friction coefficient () as a consequence (Figure 11(a)). Downstream of the peak of the bump, the velocity gradually decreases, as does the friction coefficient, consistent with the APG. A separation is observed at () in the smooth case, and negative friction is found around in the step case due to the two separated regions discussed previously. One separated region coincides with the recirculation at the bottom corner of the step, where near stagnant fluid acts as an equivalent friction-reduced ‘slope’ [37,38]. Another is the separation behind the step; however, the friction achieves a peak value immediately downstream of the separation, and is even greater than that of the smooth case at the same location. This is because the separation on the crests tilts the streamlines further upward and the velocity has to increase due to the Venturi effect.