# What is the relation between friction factor and Reynolds number for laminar flow?

## What is the relation between friction factor and Reynolds number for laminar flow?

For laminar flow, the head loss is proportional to velocity rather than velocity squared, thus the friction factor is inversely proportional to velocity. The Reynolds number must be based on the hydraulic diameter.

### How does friction factor affect pressure drop?

Pressure loss for laminar flow With laminar flow, the friction factor depends only on the Reynolds number. The higher the Reynolds number, the lower the friction factor! The pressure loss thus increases proportionally with the flow velocity – see equation (9)!

#### How does Reynolds number affect friction factor?

The friction factor is found to be a function of the Reynolds number and the relative roughness. For laminar flow (Re < 2100), the friction factor was independent of the surface roughness and it varied linearly with the inverse of Reynolds number.

**What is pressure loss due to friction?**

In fluid flow, friction loss (or skin friction) is the loss of pressure or “head” that occurs in pipe or duct flow due to the effect of the fluid’s viscosity near the surface of the pipe or duct.

**What is frictional pressure drop?**

Frictional pressure drop is the main type of pressure drop in a fluid flow. It can be of two types: major frictional pressure drop and minor frictional pressure drop. Pressure drop is a very important factor in fluid flow and should be kept at a minimum, as it increases operational cost.

## What is the value of friction factor?

f stands for the Darcy friction factor. Its value depends on the flow’s Reynolds number Re and on the pipe’s relative roughness ε / D. The log function is understood to be base-10 (as is customary in engineering fields): if x = log(y), then y = 10x.

### Does friction factor increase or decrease when the Reynolds number increases?

As the flow rate increases frictional force increases but friction factor(Darcy,Fanning) decreases with Re.

#### What is the Reynolds number for laminar flow?

If the Reynolds number < 2320, than you have laminar flow. Laminar flow is characterized by the gliding of concentric cylindrical layers past one another in orderly fashion. The velocity of the fluid is at its maximum at the pipe axis and decreases sharply to zero at the wall.

**What is the friction factor for laminar flow?**

The friction factor for laminar flow condition is a function of Reynolds number only, for turbulent flow it is also a function of the characteristics of the pipe wall. Note: Perfectly smooth pipes will have a roughness of zero. Determine Pipe friction coefficient at turbulent flow (in the most cases) Colbrook Equation:

**How is the friction factor related to the Reynolds number?**

This occurs because of the differences in friction factors: The friction factor for fluids in laminar flow is directly related to the Reynolds number (Re < 2000) and is expressed: f = Moody friction factor, Re = the Reynolds number, μ = absolute viscosity (cP (Pa s)), d = pipe inside diameter (in. (mm)), V = average velocity (ft./s (m/s)),

## How is pressure drop caused by laminar flow?

Laminar flow is characterized by the gliding of concentric cylindrical layers past one another in orderly fashion. The velocity of the fluid is at its maximum at the pipe axis and decreases sharply to zero at the wall. The pressure drop caused by friction of laminar flow does not depend of the roughness of pipe.