# What is Velocity profile: Definition and 21 Discussions

In continuum mechanics the flow velocity in fluid dynamics, also macroscopic velocity in statistical mechanics, or drift velocity in electromagnetism, is a vector field used to mathematically describe the motion of a continuum. The length of the flow velocity vector is the flow speed and is a scalar.
It is also called velocity field; when evaluated along a line, it is called a velocity profile (as in, e.g., law of the wall).

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1. ### Cylindrical rod velocity profile

Homework Statement Homework Equations 0=viscous forces 0=in-out+sum of forces(0) 2*pi*r*L*τrz evaluated at r-2*pi*r*L*τrz evaluated at r+ΔR (eq1) Dividing by volume and taking limit as δr->0 in eq1 I get : (δτrz)/(δr) =0 My question is, how did they in solution got (rδτrz)/(δr) =0, how do...
2. ### Average Velocity from Velocity Profile

Hi I have velocity profiles at different lateral position of a channel. I want to calculate average velocity from velocity profile at those position. Can you suggest me any equation or literature? I attached here a sample datasheet also.
3. ### Velocity Profile Analysis for Force Balance Equation in Fluid Dynamics

Homework Statement if we divide the force balance equation by 2pi r dx , we would get (P_(x+ Δx) ) - (P_x) + ( τ_(x + Δx) ) - τ_(x) = 0 , am i right ? why the notes give different eqaution ? Homework EquationsThe Attempt at a Solution
4. ### Transport phenomena -- Direction of shear stress

Greetings, PF! I have some questions regarding the problem I attached below. It is some sort of Couette flow variation. It's not homework, I'm just learning the basics of TP on my own. I fully solved the problem with the Navier-Stokes and continuity equations, using some assumptions in order to...
5. ### The velocity profile for viscous and non-viscous fluids

I want to know if the velocity profile is uniform for viscous fluids or not ?
6. ### Fully developed velocity profile

How would the fully developed velocity profile differ for turbulent flow?
7. ### Approximating Windshield Shape of a Car: Velocity at Points A & B

Homework Statement [/B] The shape of a car windshield is approximated in the figure below; its length is 2.0 ft and height is 1.5 ft. Obtain an equation of the windshield shape r as a function of θ, r(θ), in the polar coordinate system shown in the picture. When the car moves at 55 mph...
8. ### How to develop a Parabolic Velocity Profile in 3D tube/channel flow

i am trying to develop a Parabolic Velocity Profile in 3D tube/channel flow. for the 2D case i use u = 1.5*Um *(1-(2y/H)^2) where Um= fluid velocity y = position of solid on "y" axis (x,y) H = width of channel The above equation is not possible to used for 3D case (x,y,z). i try to...
9. ### How to scale a velocity profile

Hello, I am reading a paper in which the author describes how he scales the velocity profile of a car. He is doing this so that he can compare the velocity profiles of cars. This is an extract from the text: The first methodology consisted of evaluating the similarities between...
10. ### Velocity Profile: Fluid Mechanics Explained

What is a velocity profile in fluid mechanics? Why do they give you a ratio between the fluids velocity and a random reference velocity and why is it equal to a completely arbitrary function? Does the ratio equal a function because it is an experimental fact?
11. ### Exploring a Parabolic Velocity Profile: Basics & Calculations

I know it must relate to the velocity profile being a parabola shape and the max velocity being at the peak of the parabola - I wanted to know whether there are actual calculations I can do to show this? I only know the basics so as much details as possible would be great help...
12. ### Velocity profile and streamline equations, help please?

So far I know that dy/dx = V/U is the velocity profile. From what I've read if you know V & U and put it into that equation and the integrate it you get the equation of a streamline. is this correct? An example I have is of a velocity field defined by |U| = (B+Ay^2)e_1. The graph of the...
13. ### Navier Stokes Equation to create a Velocity Profile

Homework Statement An incompressible, viscous fluid is placed between horizontal, infinite, parallel plates. The two plates move in opposite directions with constant velocities U1 and U2. The pressure gradient in the x-direction is zero and the only body force is due to the fluid weight. Use...
14. ### Calculating the velocity profile

Hi, I need to calculate the stationary velocity profile for the Navier Stokes equations in cylindrical coordinates. Can anyone help? Thanks, Harriet
15. ### Fluid Mechanics - Turbulent flow velocity profile

Hi I'm a mechanical engineering student who has been set a question by my fluid mechanics lecturer. I need to plot the velocity flow profile of water flowing in a pipe. The information given in the question is diameter = 0.5m Re = 10^5 I know that the seventh power law is used to find...
16. ### Velocity profile between parallel plates with velocity dependent force

Homework Statement I have a channel of height H (y-direction) with three different layers. A bottom layer of height L where only viscous forces play a role and the lower boundary is a stationary plate, a middle layer of height L (so from L to 2L) where a force F depending linearly on the fluid...
17. ### Mean velocity for parabolic velocity profile

Hi, I'm making laminar fluid flow devices and want to be able to calculate the velocity as a function of distance from the channel edges. As the channels are relatively wide compared to their height I'm treating the effect of the parabolic velocity profile as negligible in the horizontal...
18. ### Can Non-Newtonian Fluid Velocity Profiles be Calculated and Drawn?

Dear Colleagues, i sent your esteem a message through the physics forum, i don't know if it reached you or not, this is my first time to join a forum :-( any way i will try to summarize my problem: 1- i need to calculate and draw the velocity profile for a Non-Newtonian fluid 2-fluid is...
19. ### Comsol-Shear stress with velocity profile

Dear all, I was trying to calculate the shear stress due to fluid flow inbetween two parallel plates from the velocity profile taken from the middle of the flow channel (along vertical axis 'y') using comsol. The solution i got is two times the analytical solution i have calculated. The...
20. ### Velocity profile from 3d velocity space data

Hi. I have a load of data objcts, each with velocity components in the cartesian x,y,z directions. I would like to find a measure of the distribution of velocity (assuming it is averaged in all directions - a good assumption). Ie i would like to end up with some 2d plot with velocity along the...
21. ### Velocity Profile of a Flow

Can someone please help me to solve this problem? Stokes’ fluid is resting in a long channel, whose boundary planes are y = a and y = -a (which do not move). At time t = 0 a pressure gradient suddenly begins to act which is constant and equals G = G e_x. If body forces do not exist, and...