Question

A fluid of viscosity 0.7 Ns/m and specific gravity 1.3 is flowing through a circular pipe of diameter 100 mm. The velocity is given as 350 m/s. Find the Reynolds Number of the flow.

a) 1.3 × 10⁵
b) 2.45 × 10⁵
c) 3.5 × 10⁵
d) 4.2 × 10⁵

Answer 1

The Reynolds Number for a fluid with a specific gravity of 1.3 and viscosity of 0.7 Ns/m^2 flowing at a velocity of 350 m/s through a 100 mm diameter pipe is calculated as 6.5 × 10^7, which is significantly higher than all the options provided and suggests turbulent flow.

Step-by-step explanation:

The question is about calculating the Reynolds Number for a fluid flow in a pipe, which is a fundamental concept in fluid mechanics, a branch of physics. To calculate the Reynolds Number (Re), we use the formula:

Re = (Density x Velocity x Diameter) / Viscosity

However, since the specific gravity is given, we can use it to find the density (ρ) of the fluid by multiplying it with the density of water (1000 kg/m³).

ρ = Specific Gravity x Density of Water = 1.3 x 1000 kg/m³ = 1300 kg/m³

Now we can plug all the values into the formula to find Re:

Re = (1300 kg/m³ x 350 m/s x 0.1 m) / 0.7 Ns/m²

Re = (45500000 kg/m´·s) / 0.7 Ns/m² = 65000000

The Reynolds Number for the flow is therefore 6.5 × 10⁷, which means the correct answer, assuming a typographical error in the options, would be closest to (c) 3.5 × 10⁵ but is actually much higher. This indicates turbulent flow.