Hi, can anyone help me to program a code for the equation with initial and boundary conditions using finite difference method
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Hi, I really need help from anyone help me with how to do a program code for governing equation with initial and boundary condition. Also, I want to plot graph velocity(u) against radius (r). The radius will be the x-axis and the range should be from 0 to 1 only. I will be really appreciated if anyone can help me. Thank you so much. Inside the coding there must be include discrerization of the governing equation. If u need , I wiil send it here right away.
The governing equation is:


Answers (1)
William Rose
on 31 Dec 2021
0 votes
@Nur Nadhirah Syed Malik, See attached.
I have left out some parts, because this sounds like a homework assignment, and you will learn by filling in the unknown parts.
4 Comments
Nur Nadhirah Syed Malik
on 31 Dec 2021
William Rose
on 31 Dec 2021
Edited: William Rose
on 1 Jan 2022
Se attached file.
I also notice that this is the simplified version of the Navier Stokes equation for fluid flow in a circular pipe, subjected to a sinusoidal predssure gradient.
This was solved analytically by Womersley.
What values can you provide for A0, A1, b1, and w? What time range? And what are the units?
The reaosn I ask about the constants is that tried solving your PDE and I found the solution to be rather unstable. By unstable, I mean that velocity has a tendency to diverge to +/- infinity, if one is not careful.
William Rose
on 31 Dec 2021
A script is attached that implements the equaitons in the document I posted earlier.
The script generates two figures, shown below:


William Rose
on 31 Dec 2021
I believe that the constant
in your equation corresponds to kinematic viscosity:
=viscosity/density. I also believe that the units for A0 and A1 are pressure/length, and that the terms A0+A1*cos wt correspond to the pressure difference divided by the length of the tube. Are those beliefs correct? The Womersley number for pulsatile flow is
. If I am correct about
, then the Womersley number for this problem (in which R=1) is
.
=viscosity/density. I also believe that the units for A0 and A1 are pressure/length, and that the terms A0+A1*cos wt correspond to the pressure difference divided by the length of the tube. Are those beliefs correct? The Womersley number for pulsatile flow is Categories
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