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Water Hydraulics
Published in Frank R. Spellman, The Science of Water, 2020
A pitot tube is a point velocity-measuring device (see Figure 3.27). It has an impact port; as fluid hits the port, its velocity is reduced to zero and kinetic energy (velocity) is converted to potential energy (pressure head). The pressure at the impact port is the sum of the static pressure and the velocity head. The pressure at the impact port is also known as stagnation pressure or total pressure. The pressure difference between the impact pressure and the static pressure measured at the same point is the velocity head. The flow rate is the product of the measured velocity and the cross-sectional area at the point of measurement. Note that the pitot tube has a negligible permanent pressure drop in the line, but the impact port must be located in the pipe where the measured velocity is equal to the average velocity of the flowing water through the cross section.
Study on slamming of the foam core carbon fibre V-shaped plate frame
Published in C. Guedes Soares, Developments in the Collision and Grounding of Ships and Offshore Structures, 2019
Z. Qin, T. Zhang, L. Zhang, Z. Chen
The carbon fibre plate frame structure is rigidly mounted on the impact tower track, and a specific fixed bracket and pulley are designed for the plate frame to ensure the installation and falling posture of the plate frame. According to the required impact speed, the motor is used to raise the frame structure to a certain height, and the electromagnetic decoupling device is opened to enable the plate frame to free fall to the water surface, thereby realizing the water drop impact of the plate frame. The LTS400 photoelectric door switch is used, with the high-frequency data collector, to measure the instantaneous speed when the plate hits the water surface. The impact pressure and stress of the plate are measured using a pressure sensor and a strain gauge, respectively.
Flow of Incompressible Fluids
Published in Raymond Mulley, Flow of Industrial Fluids—Theory and Equations, 2004
A device such as a Pitot tube measures the impact pressure and the static pressure at a point. Impact pressure is the static pressure at the point plus the pressure difference created by decelerating the fluid to zero velocity. The point velocity is computed from the difference between this impact pressure and the static pressure at the section. This difference is often called the velocity head. The word “head” arises from the use of open manometers to measure differential pressure in early hydraulic work.
Experimental study on the pressure of impulse waves generated by landslides on a bank slope
Published in Marine Georesources & Geotechnology, 2021
Ting Cao, Pingyi Wang, Jielong Hu, Zhenfeng Qiu, Pengchao He
The bank slope was subject to a considerable impact as the wave ran up, fell back, and impacted. From the comparison of all the working conditions, it was inferred that there are two kinds of pressure which are shown in Figure 7. First, the pulsating pressure, which is defined as the value from the zero level of the pressure cell to the following peak pressures with a long cycle. Furthermore, only the maximum pulsating pressure (Pc1), which refers to the first pressure peak with the maximum value is discussed herein. Second, impact pressure which is defined as the value from the zero level of the pressure cell to the following peak pressures with a corresponding rising or compression time △t, and it was short in duration but large in magnitude. Only the maximum impact pressure (Pim) is discussed herein, and it usually occurred when the second wave train met the first wave train that fell back, at which point the water broke locally, impacted the bank slope, and caused turbulence at the water surface. Notably, the impact pressure is included in the cushion pressure which is mainly determined by identifying whether run-up water flow thoroughly fell back when it impacted the bank slope. Therefore, impact pressure was the total pressure generated as water impacted the bank slope.
Damage prediction and test validation of bird impacts on aircraft leading edge’s structures
Published in International Journal of Crashworthiness, 2022
Fatima-Zohra Belkhelfa, Salah Boukraa
Because the impact process is basically fluid dynamic, the characteristic pressures are the Hugoniot, or impact, pressure and the flow, or stagnation, pressure. Both of these pressures depend only on the impact velocity and the material properties of the bird (i.e. density and shock velocity). The magnitudes of these pressures should not vary with bird size, however, the spatial and temporal distribution of pressure should. Since birds of different mass are, however, geometrically similar (i.e. they have a similar length to diameter ratios), pressure distributions should scale linearly with bird dimensions.