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Reynolds’ number is a dimensionless quantity used to predict the nature of fluid flow, whether it will be laminar, transitional, or turbulent
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What is Reynolds number? Definition.
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Reynolds number is a dimensionless
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quantity used to predict the nature of
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fluid flow whether it will be laminer,
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transitional or turbulent. Explanation
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Reynolds number compares the effects of
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inertial forces to viscous forces in a
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flowing fluid. It helps physicists and
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engineers understand how a fluid behaves
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as it moves through pipes over surfaces
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or around objects. Low Reynolds number
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means viscous forces dominate and the
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flow is smooth and orderly. High
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Reynolds number means inertial forces
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dominate and the flow becomes chaotic
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and turbulent. Imagine imagine water
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flowing gently from a tap. It forms
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smooth straight lines. Now open the tap
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fully and the water splashes and swirls
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unpredictably.
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Reynolds number explains why this change
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in flow happens. In simple terms,
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Reynolds number tells us whether a fluid
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will flow smoothly or turbulently.
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Formula or concept. Reynolds number is
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calculated using the velocity of flow
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characteristic length density and
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viscosity of the fluid. Reynolds number
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equals density time velocity time
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characteristic length/ viscosity. Where
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density equals density of the fluid,
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velocity equals speed of the fluid.
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Characteristic length equals diameter of
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pipe or size of object. Viscosity equals
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dynamic viscosity of the fluid. For flow
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in a pipe, Reynolds number less than
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2,000 indicates laminer flow. Between
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2,00 and 4,000 indicates transitional
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flow. Greater than 4,000 indicates
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turbulent flow. Key points. It has no
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unit. Predicts type of fluid flow.
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Depends on velocity and viscosity.
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Important in fluid mechanics used in
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pipe and aerodynamic studies. Examples
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water flowing slowly in a narrow pipe.
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Air flow around a moving car. Blood flow
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and arteries. O moving through
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pipelines. Applications pipe flow
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analysis. Aerodynamics and aircraft
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design. Engineering fluid systems.
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Medical blood flow studies. Physics
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education. Question. Why does increasing
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fluid speed increase Reynolds number?
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Answer: Increasing fluid speed increases
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inertial forces relative to viscous
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forces, making turbulent flow more
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likely and increasing Reynolds number.
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Solved problem question and answer.
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Question. A fluid of density 1,00 kilog
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per meter flows through a pipe of
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diameter 0.05 m at a speed of 2 m/s.
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If its viscosity is 0.01 p. Calculate
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the Renault's number. Answer. Density
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equals 1,00 kilog per meter. Velocity
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equals 2 m/s. Diameter equals 0.05 m.
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Viscosity equals 0.01 p. Reynolds number
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equals 1,2*
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0.05.
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0.01.
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Reynolds number equals 10.
#Physics