Search results
Results from the WOW.Com Content Network
A new parameter, effective Air Changes per Hour (called ACHH by Mojtaba Zabihi et. al. [8]), which incorporates both the flow rate and large-scale airflow patterns, could provide a more accurate measure of how efficiently air is supplied and circulated within a room. This is particularly important for effectively managing airborne disease spread.
Even in the case of laminar flow, where all the flow lines are parallel to the length of the pipe, the velocity of the fluid on the inner surface of the pipe is zero due to viscosity, and the velocity in the center of the pipe must therefore be larger than the average velocity obtained by dividing the volumetric flow rate by the wet area.
A hot-wire anemometer, for example, registers decreases in wire temperature, which can be translated into airflow velocity by analyzing the rate of change. Convective cooling is a function of airflow rate, and the electrical resistance of most metals is dependent upon the temperature of the metal, which is affected by the convective cooling. [5]
For air flow at room temperature, when the outlet pressure is less than 1/2 the absolute inlet pressure, the flow becomes quite simple (although it reaches sonic velocity internally). With C v = 1.0 and 200 psia inlet pressure, the flow is 100 standard cubic feet per minute (scfm).
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 particle Reynolds number is important in determining the fall velocity of a particle. When the particle Reynolds number indicates laminar flow, Stokes' law can be used to calculate its fall velocity or settling velocity. When the particle Reynolds number indicates turbulent flow, a turbulent drag law must be constructed to model the ...
Given the distribution of bound vorticity and the vorticity in the wake, the Biot–Savart law (a vector-calculus relation) can be used to calculate the velocity perturbation anywhere in the field, caused by the lift on the wing. Approximate theories for the lift distribution and lift-induced drag of three-dimensional wings are based on such ...
It can be successfully applied to air flow in lung alveoli, or the flow through a drinking straw or through a hypodermic needle. It was experimentally derived independently by Jean Léonard Marie Poiseuille in 1838 [1] and Gotthilf Heinrich Ludwig Hagen, [2] and published by Hagen in 1839 [1] and then by Poiseuille in 1840–41 and 1846. [1]