## What is my Reynolds number?

# What is my Reynolds number?

Table of Contents

## What is my Reynolds number?

Reynolds number (Rn) is defined as Rn=(ρVL)/μ=(VL)/ν, where V is the fluid velocity relative to the body and L is a typical length.

## How is Reynolds calculated?

The Reynolds number (Re) of a flowing fluid is calculated by multiplying the fluid velocity by the internal pipe diameter (to obtain the inertia force of the fluid) and then dividing the result by the kinematic viscosity (viscous force per unit length).

## How do you convert Reynolds number?

The Reynolds number Re then becomes:

- Re = (r * V * dV/dx) / (mu * d^2V/dx^2) The gradient of the velocity is proportional to the velocity divided by a length scale L.
- Re = (r * V * V/L) / (mu * V / L^2) Re = (r * V * L) / mu.
- nu = mu / r. Re = V * L / nu.

## How is Reynolds number calculated for airfoil?

The Reynolds number is based on a length, which is usually the chord length of an airfoil (in two dimensions) or the chord length of a wing. A 1/4 scale model would fly at roughly 40 m/s and thus would have a tip Reynolds number of 40 * 1.0/4 * 70000 = 0.7 Millions, which is only 1/10 of the full scale plane.

## How high can Reynolds number be?

In typical applications, N is often in the range of 10 to 20, which translates to a maximum Reynolds number for accurate computations of only about 400, not a very large number!

## Why does Reynolds number increase with density?

The formula says that the value of Reynolds number is directly proportional to density of the blood, the blood’s velocity and the diameter of the blood vessel. Increasing the magnitude of any of these parameters will result in an increase in Reynolds number, and add turbulence to the blood flow.

## How do you test laminar flow?

The flow profile of laminar flow in a tube can be calculated by dividing the flow into thin cylindrical elements and applying the viscous force to them. Another example is the flow of air over an aircraft wing.