In
fluid dynamics
In physics, physical chemistry and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids – liquids and gases. It has several subdisciplines, including (the study of air and other gases in motion ...
, the
fluid
In physics, a fluid is a liquid, gas, or other material that may continuously motion, move and Deformation (physics), deform (''flow'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are M ...
flow is often decomposed into a mean flow and
deviations from the
mean
A mean is a quantity representing the "center" of a collection of numbers and is intermediate to the extreme values of the set of numbers. There are several kinds of means (or "measures of central tendency") in mathematics, especially in statist ...
. The
averaging
In ordinary language, an average is a single number or value that best represents a set of data. The type of average taken as most typically representative of a list of numbers is the arithmetic mean the sum of the numbers divided by how many nu ...
can be done either in space or in time, or by
ensemble averaging.
Example
Calculation of the mean flow may often be as simple as the
mathematical mean: simply add up the given flow rates and then divide the final figure by the number of initial readings.
For example, given two
discharges (''Q'') of 3 m³/s and 5 m³/s, we can use these flow rates ''Q'' to calculate the mean flow rate ''Q''
mean. Which in this case is ''Q''
mean = 4 m³/s.
See also
*
Generalized Lagrangian mean
References
*
*
{{fluiddynamics-stub
Fluid dynamics