Numericals 2 On Height Of Protection - Turbulent Flow - Fluid Mechanics 2

TL;DR

The video explains how to calculate the maximum permissible height of protrusions on a pipe in order for it to work as a smooth pipe in a turbulent flow.

Transcript

hello friends in this video we are going to calculate the height of cottages through our numerical so let's move on to video let's see the numerical a pipeline of daya 0.3 meter carries the oil at the rate of 500 liter per second if the specific gravity of oil is 0.8 and its kinetic viscosity is zero point zero 23 Stokes later mine maximum permissi... Read More

Key Insights

• ❓ The hydrodynamic layer of a pipe determines whether it is hydrodynamically smooth or rough.
• 💐 The calculation of the Reynolds number helps determine if the flow is turbulent or laminar.
• 🧑‍🏭 The friction factor (f) is used to calculate the shear stress (τ) on the pipe.

Questions & Answers

Q: What is the hydrodynamic layer of a pipe?

The hydrodynamic layer refers to the laminar sublayer below the roughness of a pipe where the flow is smooth. If the pipe roughness is smaller than the thickness of the laminar sublayer, it is considered hydrodynamically smooth.

Q: How is the average velocity of the flow calculated?

The average velocity (u bar) is determined by dividing the discharge rate by the pipe's cross-sectional area. In this case, it is 7.64 m/s.

Q: How do you determine if the flow is turbulent or not?

By calculating the Reynolds number using the formula Re = (u bar x D)/ν, where u bar is the average velocity, D is the pipe diameter, and ν is the kinematic viscosity. If the Reynolds number is above 4000, the flow is turbulent.

Q: How is the height of protrusions calculated?

The formula used is u bar/u star = 2.5 * log(R/k + 8.5). By solving this equation, the height of protrusions (k) is found to be 5.45 mm.

Summary & Key Takeaways

• The video discusses the concept of the hydrodynamic layer of a pipe and the difference between hydrodynamically smooth and rough pipes.

• The given data includes the pipe diameter, oil discharge rate, specific gravity, and kinematic viscosity.

• Using the Reynolds number and friction factor, the video calculates the height of protrusions allowed on the pipe.