Model of forced turbulence for pulsing flow
1
Lviv Polytechnic National University
Submission date: 2020-01-07
Final revision date: 2020-02-23
Acceptance date: 2020-03-03
Online publication date: 2020-03-10
Publication date: 2020-03-10
Diagnostyka 2020;21(1):89–96
KEYWORDS
TOPICS
ABSTRACT
Taking into consideration the Stokes equation, the tangential friction stresses according to Newton and the Reynolds equationі, the differential equation of the velocity change in radius is developed taking into account the pulsating component of the friction forces in the turbulent flow. Turbulence is defined as the impulse component of a flow, characterized by a pressure drop along a dynamic length of flow, a frequency response, and an oscillation amplitude of the pressure drop of pulse (which is given by the time equation of the oscillation). The velocity distribution along the radius of the hose in the time interval of one second was modelled for pressure drops in the range from 6000 to 18000 Pa and the amount of transported medium in the range from 1.667·10-5 to 6.667∙10-5 m3, which corresponded to the length of pulse plug. The dynamic viscosity of the medium (milk) of 1.79 ∙ 10-3 Pa∙s and its density of 10273 N·s2/m4 were accounted at the simulation. The developed analytical dependence of the velocity of the forced turbulence of the pulsating flow allows to calculate the absolute value of the velocity at a given point of cross-section of the pipeline.
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