How to calculate friction factor ?

More Mohammed Hussein's questions See All

What are the values needed for gabor filter's parameter for cifar10 data?

Hi, I implemented a code to gabor filter cifar10 data but the images after being filtered and stacked are not clear like the original images. I think the problem is in the way I am using the...

03 March 2021 6,317 1 View

Is the a way to contol flow (Flow velocity) without impacting pressure value?

I have a pipe with 10 mm in Diameter and 2 bar pressure, the fluid velocity is 200 m/s, the fluid is air. is there a way to reduce velocity without affecting the pressure value?

25 February 2021 7,187 3 View

Is it possible to set a breakpoint at a specific DYNAMIC instruction using the GNU Debugger (GDB)?

Using GDB, it is straightforward to debug and monitor a target program by setting a break-point at a specific instruction, since the instruction addresses are known. However, we have two...

24 February 2021 1,598 2 View

Can anyone suggest a topic for the Impact of AI and ML in the financial institutions?

I am currently doing my Master Thesis in FinTech and I am thinking of doing my project on the impact of AI and ML on the financial industry but as the impact of these technologies on the industry...

21 February 2021 7,128 3 View

Where I can find materials to learn Fuzzy VIKOR methodology?

Please suggest ways to learn Fuzzy VIKOR methodology in a best possible way. And is there any toolkit available for the same? Thank you in advance.

20 February 2021 8,271 3 View

What cause the beating of this signal?

I am trying to simulate the impact of a sinusoidal force on a Beam, yet I registred this beating signal (Displacement by time). The freaquency of excitation was the same as the first natural...

19 February 2021 5,872 3 View

Can someone help me with this error that I am getting while estimating a VAR model in R?

I am using annual time series data to estimate a VAR model in R. However, when I run the command to find the optimal lag length, I get the following error: Fehler in VARselect(data, lag.max = 10,...

18 February 2021 9,647 3 View

How to apply a voltage sinusoidal/harmonic load in ANSYS APDL?

Hello all, I want to simulate a Dielectric Elastomer Actuator DAE (an electrostatic-Structural analysis). I want to apply various voltages and frequencies into the DEA in the form of sine wave....

13 February 2021 3,261 3 View

How to calculate time needed to evacuate a pressure from a tank using a pump?

Dear I have an air reservoir with 50 bar pressure , this reservoir is fed by 2 bar air pressure source, I would like to instal air pump ( 30 m3/h ) to evacuate the 2 bar fed pressure so I always...

06 February 2021 3,520 3 View

Observation instrument for classroom activity in consecutive interpreting?

Hello everybody My research involves an intervention where an instructor delivers a training course to students. My role as a researcher is to write down observations. Do you have any idea about...

03 February 2021 6,853 3 View

Why are the velocities so high in my Boussinesq approximation Fluent simulation?

Hello, I have a mechanism where air rises due to convective flows. In this simulation, nothing is driving the air except this. I understand that the Boussinesq approximation only works for small...

02 March 2021 4,910 3 View

How to show arrows over the streamlines in CFD-post?

I follow this to make streamlines like the photos attached below: (software- CFD post-processing) First I plot the 2D streamline over a surface "streamline 1". them I plot a vector by the...

01 March 2021 8,668 3 View

What is recommended for solid domain in ANSYS FLUENT?

Should I mesh the solid domain ? or should I use wall thickness? or Shell conduction? for Heat Transfer between two fluids of a Heat Exchanger. what is recommended?

01 March 2021 9,785 3 View

Can Virtual Servers (remote dekstop manager) run heavy ANSYS Fluent CFD simulation ?

I have a virtual machine. My host Pc specs are not that good thats why i went for virtual servers. so basically my host pc has 8gb of ram with nvidia quadro k2200 4Gb DDR5 GPU ,processor intel...

01 March 2021 8,415 1 View

How to increase mesh quality of a cfd model in ansys fluent?

How can one improve mesh skewness, orthogonality, aspect ratio?

28 February 2021 7,730 3 View

How do you mesh a thin solid in Fluent?

Hello, I have used the shell function on SpaceClaim to create thin solids for the model I am studying. These are contained within an enclosure for my study. I chose this approach as it avoids the...

24 February 2021 8,856 3 View

How to extract the y+ value from fluent ?

I am doing a 3D steady simulation of a wind rotor using Ansys Fluent. In order to have a y+ of 1, I created 10 inflation layers using total layer thickness method, and I started a first...

23 February 2021 2,819 3 View

Help with assigning pressure boundary conditions in FLUENT on a large structure?

Hello, I created a very tall tower (>1000m) and applied pressure boundary conditions at the inlet (bottom) and outlet (top) that correspond to the pressure are their relative altitudes....

22 February 2021 9,972 4 View

How do I add a udf to Ansys fluent and does it need to be compiled before hand ?

I have a Define_CG_Motion udf written in c where do I add it to my Ansys fluent project and does it need to be compiled before that?

21 February 2021 9,347 3 View

How do you integrate the 'friction' variable Xi in the Nose - Hoover Thermostat in order to apply it to a molecular dynamics simulation?

Everything tells you the derivative of Xi, but not how integrate the value to implement it into a simulation. How do you do this?

21 February 2021 6,481 1 View

Maziar Gheshlaghi

Ensure that you have the necessary boundary conditions and material properties set up.

Create a surface monitor by selecting “Surface Monitors” under the “Reports” menu.

In the “Surface Monitors” window, click “Add” to create a new surface monitor.

In the “Surface Monitor Data” window, specify the name of the surface monitor and select the surface of the wall where you want to calculate the friction factor.

Under “Output Variables,” select “Coefficient of Shear Stress (wall) - Magnitude” and “Wall Shear Stress (wall) - Magnitude.”

Under “Report Parameters,” specify the frequency and duration of the surface monitor data collection.

Click “OK” to create the surface monitor.

Simulate your project to obtain the data at your specified time steps.

Once the simulation is done, go to the “Reports” menu and select “Surface Monitors.”

In the “Surface Monitors” window, select your created monitor and click “Plot.”

In the “Plot Properties” window, select “Wall Shear Stress (wall) - Magnitude” on the y-axis and “Coefficient of Shear Stress (wall) - Magnitude” on the x-axis.

Click “OK” to generate the plot.

The friction factor for the wall can be calculated as the slope of the plot, which is the ratio of the wall shear stress over the dynamic pressure.

Note: This method assumes that the flow is fully developed and in a turbulent regime. If the flow is laminar, the friction factor is calculated using different equations.

Kristaq Hazizi

In ANSYS Fluent, the friction factor can be calculated using the wall functions or by solving the full turbulent flow equations. I'll explain both methods below:

Method 1: Using Wall Functions

Set up your simulation in ANSYS Fluent, including the geometry, boundary conditions, and turbulence model.

Specify the wall function approach by selecting the appropriate turbulence model. Commonly used models for wall-bounded flows include the k-epsilon (k-ε) and the Reynolds-averaged Navier-Stokes (RANS) models.

Run the simulation until it converges.

Once the simulation is complete, go to the Solution menu and select Reports -> Surface Integrals.

In the Surface Integrals panel, choose the wall(s) for which you want to calculate the friction factor.

Enable the "Shear Stress" option and click on the Calculate button.

ANSYS Fluent will compute the wall shear stress. The friction factor (f) can be calculated using the following equation:f = τw / (0.5 * ρ * U^2)Where: τw is the wall shear stress obtained from Fluent. ρ is the fluid density. U is the free stream velocity.

Method 2: Solving the Full Turbulent Flow Equations

ANSYS Fluent will compute the wall shear stress. The friction factor (f) can be calculated using the following equation:f = (τw / (0.5 * ρ * U^2)) * (L / D)Where: τw is the wall shear stress obtained from Fluent. ρ is the fluid density. U is the free stream velocity. L is the characteristic length of the flow (e.g., pipe length). D is the hydraulic diameter of the flow (e.g., pipe diameter).

Note that the above methods assume that you are dealing with a turbulent flow regime. The friction factor calculations are typically used for pipe flows, where it is commonly defined as the Darcy friction factor (f). The methods mentioned here can be applied to other wall-bounded flows as well, with appropriate modifications as needed.

Remember to consult the ANSYS Fluent documentation or user guide for specific details and guidance on using the software for your particular case.