The Reynolds number is an important parameter in Transport Phenomena. It is used extensively in many calculations dealing with

**fluid flow**, mass transfer and heat transfer. It is the ratio of the inertial forces to the**viscous**forces and depends on a**characteristic length**, velocity, density and viscosity of the fluid.What does the Reynolds number tell us?

In fluid mechanics, the

**Reynolds number**(Re) is a dimensionless**number**that gives a measure of the ratio of inertial forces to viscous forces and consequently quantifies the relative importance of these two types of forces for given flow conditions.1

## What do you mean by steady flow?

Definition of

**steady flow**. : a**flow**in which the velocity of the fluid at a particular fixed point does not change with time — called also stationary**flow**; compare uniform**flow**.2

## What do you mean by turbulent flow?

**Turbulent flow**, type of fluid (gas or liquid)

**flow**in which the fluid undergoes irregular fluctuations, or mixing, in contrast to laminar

**flow**, in which the fluid moves in smooth paths or layers. In

**turbulent flow**the speed of the fluid at a point is continuously undergoing changes in both magnitude and direction.

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## What is the definition of Stokes law?

the

**law**that the force that retards a sphere moving through a viscous fluid is directly proportional to the velocity of the sphere, the radius of the sphere, and the viscosity of the fluid. the**law**that the frequency of luminescence induced by radiation is usually less than the frequency of the radiation.4

## What is the Venturimeter?

**Venturimeter**is the most widely used device to measure the discharge through the pipe. A venturi is a converging-Diverging nozzle of circular cross-section.

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## What is the characteristic length?

In physics, a

**characteristic length**is an important dimension that defines the scale of a physical system. Often, such a**length**is used as an input to a formula in order to predict some**characteristics**of the system. Examples: Reynolds Number. Biot number.6

## What is the Nusselt number?

In heat transfer at a boundary (surface) within a fluid, the

**Nusselt number**(Nu) is the ratio of convective to conductive heat transfer across (normal to) the boundary. In this context, convection includes both advection and diffusion.7

## What is the Moody chart?

In engineering, the Moody chart or Moody diagram is a graph in non-

**dimensional**form that relates the**Darcy-Weisbach friction factor**f_{D}, Reynolds number Re, and relative roughness for fully developed flow in a**circular**pipe. It can be used to predict pressure drop or flow rate down such a pipe.8

## What is the Weber number?

The

**Weber Number**is a dimensionless value useful for analyzing fluid flows where there is an interface between two different fluids. The**Weber Number**is the ratio between the inertial force and the surface tension force and the**Weber number**indicates whether the kinetic or the surface tension energy is dominant.9

## Why do we need Nusselt number?

The physical interpretation of

**Nusselt number**is the enhancement of heat transfer due to convection over conduction alone. With Nu >1, the fluid motion enhances heat transfer by advection. The**Nusselt number**is of paramount**importance**because it contains the heat transfer coefficient information.10

## What is the coefficient of drag?

The

**drag coefficient**is a common measure in automotive design as it pertains to aerodynamics.**Drag**is a force that acts parallel and in the same direction as the airflow. The**drag coefficient**of an automobile impacts the way the automobile passes through the surrounding air.11

## What is meant by viscous forces?

A measure of a fluid's resistance to flow.

**Viscous forces**in a fluid are proportional to the rate at which the fluid velocity is changing in space; the proportionality constant is the**viscosity**.12

## What is the Grashof number?

The

**Grashof number**(Gr) is a dimensionless**number**in fluid dynamics and heat transfer which approximates the ratio of the buoyancy to viscous force acting on a fluid. It frequently arises in the study of situations involving natural convection and is analogous to the Reynolds**number**.13

## What is the viscosity of water?

The dynamic

**viscosity of water**is 8.90 × 10−4 Pa. · s or 8.90 × 10−3 dyn. · s/cm2 or 0.890 cP at about 25 °C.**Water**has a**viscosity**of 0.0091 poise at 25 °C, or 1 centipoise at 20 °C. As a function of temperature T (K): (Pa.14

## What is inertia force in fluid?

As in classical mechanics, a

**force**that can counteract or counterbalance this**inertial force**is the**force**of friction (shear stress).In the case of**fluid**flow, this is represented by Newtons law, τ x = μ d v d y . This is only dependent on the viscosity and gradient of velocity.15

## What is the coefficient of discharge?

In a nozzle or other constriction, the

**discharge coefficient**(also known as**coefficient of discharge**) is the ratio of the actual**discharge**to the theoretical**discharge**, i.e., the ratio of the mass flow rate at the**discharge**end of the nozzle to that of an ideal nozzle which expands an identical working fluid from the16

## What is a dimensionless number?

In dimensional analysis, a

**dimensionless**quantity (or more precisely, a quantity with the dimensions of 1) is a quantity without any physical units and thus a pure**number**. Such a**number**is typically defined as a product or ratio of quantities which do have units, in such a way that all the units cancel out.17

## What is the formula for Reynolds number?

**Reynolds number**is used to check whether the flow is laminar or turbulent. It is denoted by R

_{e}. This

**number**got by comparing inertial force with Viscous force.

**Reynolds number formula**is used in the problems to find the Velocity (V), density ( ), Viscosity ( ) and diameter (L) of the fluid. It is dimensionless.

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## What is the purpose of a Venturi meter?

Venturi meters are flow measurement instruments which use a converging section of pipe to give an increase in the flow velocity and a corresponding pressure drop from which the flowrate can be deduced. They have been in common use for many years, especially in the

**water**supply industry.19

## What is the ratio of the Reynolds number?

The Reynolds number (Re) is the ratio of inertial resistance to viscous resistance for a flowing fluid. The Reynolds number is a

**non**-dimensional (unitless) factor governing resistance due to viscosity (among other things). Reynolds, Osborne."