# ANSWERS CLASS NOTES

## design.

### What is Newton’s Law of Viscosity?

##### τ= μ du/dy τ is shear stress between two adjacent layers of a moving fluid du change in velocity in x direction (direction of motion) dy is the distance (perpendicular to du) between the two layers in y direction NOTE du is in x direction and dy is in y direction du/dy becomes shear strain or velocity gradient in y direction μ is constant of proportionality & is  Dynamic viscosity. μ = τ/ (du/dy) τ =N/m2 du = m/s dy = m Therefore, Units of viscosity are Ns/m2.
1. State the basic principle used in discharge measurement in Venturimeter and Orifice meter?

Bernoulli’s Theorem deals with conservation of energy. Pressure head changes into kinetic head. Use pressure difference the measurement of discharge in the Venturimeter and Orifice meter.

### 31. What is a Froude’s number? What is its significance?

#### In appearance, it has similarity with Mach number. Froude’s number is used in a fluid flow around marines, over spillways or flow over the weirs in open channels.

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