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In fluid dynamics, dynamic pressure (denoted by q or Q and sometimes called velocity pressure) is the quantity defined by: [1] = where (in SI units): q is the dynamic pressure in pascals (i.e., N/m 2, ρ (Greek letter rho) is the fluid mass density (e.g. in kg/m 3), and; u is the flow speed in m/s.
The Dall tube is a shortened version of a Venturi meter, with a lower pressure drop than an orifice plate. As with these flowmeters the flow rate in a Dall tube is determined by measuring the pressure drop caused by restriction in the conduit. The pressure differential is typically measured using diaphragm pressure transducers with digital readout.
Both laboratory and field test results show that the VMCM is capable of making accurate measurements of horizontal velocity in the upper ocean. The VMCM is the current standard for making high quality velocity measurements in near-surface regions [2] and it has been used for benchmarking other current meters. [3] [4]
p Total is the total fluid pressure. p Static is the static pressure, which strictly depends on depth. p Dynamic is the fluid pressure caused by fluid motion. Since water is an incompressible fluid, the dynamic pressure component of the total pressure can be expressed in terms of the water density and the water velocity as is shown in Equation 2.
In its simplest electronic form, the instrument consists of an air bottle connected to the external atmosphere through a sensitive air flow meter. As the aircraft changes altitude, the atmospheric pressure outside the aircraft changes and air flows into or out of the air bottle to equalise the pressure inside the bottle and outside the aircraft.
Pressure head is a component of hydraulic head, in which it is combined with elevation head. When considering dynamic (flowing) systems, there is a third term needed: velocity head. Thus, the three terms of velocity head, elevation head, and pressure head appear in the head equation derived from the Bernoulli equation for incompressible fluids:
Schematic view of a flow sensor. An ultrasonic flow meter is a type of flow meter that measures the velocity of a fluid with ultrasound to calculate volume flow. Using ultrasonic transducers, the flow meter can measure the average velocity along the path of an emitted beam of ultrasound, by averaging the difference in measured transit time between the pulses of ultrasound propagating into and ...
The meter is "read" as a differential pressure head in cm or inches of water. Video of a Venturi meter used in a lab experiment Idealized flow in a Venturi tube The Venturi effect is the reduction in fluid pressure that results when a moving fluid speeds up as it flows from one section of a pipe to a smaller section.