# Friction factor determination for fluid flow inside pipes

Initial Publication Date: December 1, 2021

## Summary

This activity aims to generate a program that computes the Fanning friction factor for any user input conditions (pipe diameter, bulk flow velocity, surface roughness) for water flowing inside a pipe. Considerations for both laminar and turbulent flow are included, as well as varying levels of pipe surface roughness.

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## Learning Goals

The main objective of this activity is to reinforce the understanding of students on the concept of skin friction and frictional losses in piping systems in general. After the activity, students will have a greater understanding of the logic behind selecting the correct equation for determining Fanning friction factors for a wide variety of conditions of fluid flow inside pipes. This activity further develops the logical thinking skills of the students as it requires higher order thinking to incorporate user inputs to the program.

## Context for Use

This is an online activity for a Chemical Engineering Laboratory or General Fluid Mechanics course. It can be used as a teaching aid for skin friction discussions or simulations. The students only need basic Matlab skills to create the code (usually it just needs nested if-else statements). A background in the principles of momentum transport is useful but not absolutely needed. A brief lecture on skin frictional losses in piping systems would help the students understand the activity.

## Description and Teaching Materials

The activity simply requires the students to generate a program that will return the value of Fanning friction factor after asking the user to input pipe diameter, water bulk velocity, and pipe surface roughness with the appropriate units. The program should be able to differentiate between laminar and turbulent flow, as well as between smooth and rough surface assumptions. The equations needed are given on the attached activity sheet.
Student handout for Skin Friction Simulation Experiment (Acrobat (PDF) 201kB Dec1 21)

## Teaching Notes and Tips

The instructor should begin with a brief discussion on the equations to be used given on the file above. Afterwards, the instructor can also give an idea on the nested if-else function that can be used to simplify the task of determining which equation to use for laminar and turbulent flows, and smooth and rough surface assumptions.

## Assessment

The students have achieved the objectives of the activity if their program:
1. returns the correct Fanning friction factor
2. correctly classifies the flow as either laminar or turbulent
3. correctly uses the equations for smooth and pipe surface assumptions