hi guys I'm Olivia now I'm gonna run through Fluent in which we do
computational fluid dynamics modeling so just load Fluent and we will pick the option as
processing option as parallel and we run two processes
so essentially what it does is it's running two processes simultaneously and
the work directory we will pick the directory that that you want to work on
so in this case I pick this and click OK
so we have come to this page here so what we do is we will load will read the mesh
and because I was working on the directory that I want to work on the
mesh file is already there so what you can do is to put your mesh file in the
directory that you want to work on I'll just click the mesh folder I want and
click OK so now Fluent is loading the mesh that
I selected it, right so it says down here but it's nothing on the display so what
we do is we right-click we display and display mesh you can pick what you want too
and then click display so now we have the geometry that we want so now we have
to set up different parts to run a CFD model so let's just start with models
here and I'll define my model I will use K-Omega and the SST model so SST model
essentially is called the shear stress transport model and provides good
prediction on flow separation so we picked that for our work and click okay
so here you can do different things like scaling the mesh check if the mesh is
alright decide whether you want to do a steady or transient simulation but now
we will just do a steady state, so once you set up the model we will move on to
material and because you're working on an artery and what's in the artery
basically blood so we will define our material to be blood so if you know that
some of you might know that blood is a non-newtonian fluid but as you run the
simulation we were just defining it as a Newtonian fluid with the density
of 1060 and the viscosity of 0.0035 and
once we're done with that we click change or create and there are others if
you want to.. and just click yes
setting a constant value for our fluid called blood but if you wanna do a
non-newtonian simulation what you can do is you can define different function and
different UDF so that's what I call you the user-defined function and
essentially setting the blood to run as non-newtonian fluid but in this case you
will just do make it a Newtonian fluid so once we set up the material you will
move to boundary conditions so a_in and a_out are our velocity inlets so we will set
the velocity set it as velocity inlets and the velocity magnitude will be 0.5
I'll put it as 0.5 for for this case but you'll be given the values for your
work so use the values that it's given and for the type of velocity aout
similar I'm just gonna set it as velocity Inlet and set it as 0.3 similar thing
you will need to set the velocity based on the ones that is given to you so the
wall this is just gonna be wall yeah it's correctly set up and Vout will be
the outflow so that's boundary conditions boundary conditions pretty
important for you to set up a correct simulation and once we finish with
boundary conditions setting the material and the model, we will move on to
the solution bit. So the solution bit is essentially where we define different
bits so let's start with monitoring so in monitors you can pick residual or
report false or report plot. So for residual it's given as 0.001 that's basically
yeah gives you good information on the work that you're doing so to make it
more accurate essentially the residual is where you set your convergence so I
will just put it as 0.0001 for all the criteria
usually when we run simulations 10 to a power of -4 or 10 to power -5
is the ideal ones but because the mesh is not very fine in this case due to the
license restriction 10 to a power of -3 or -4 will be sufficient for your work so
I'll click OK so I set the residual and the report files so what you can do is
you can set different report files that you want to have and so you can browse
and see where you want to put your report file or you wanna pop plot you
can set and click new same thing what you wanna what you want to see surface
report area flow rate different things so that's depending on what you want to
look at in this case I'll just not set anything I'm just giving you the basic
idea of how it works so once you're done with that we'll just
do the initialization hybrid standard it's fine
so I'm initializing it
once you have done it with that we will set up our calculation activity whether
you want it to autosave what it does is it saves every single file based on the
iteration number of the iteration that you give so if you want it to save every
file off the 10 iteration then just put 10 but yeah up to you and run
calculation so after I click that so the number of iterations I get essentially
what it means is how many times you want the computer to do the math to run the
iterations before we just convergence so convergence is the values that you set
at the residual if you remember so I'll just put 3,000 so what the computer does
it runs 3000 iteration and if until the 3,000 iteration
it hasn't reached the residual that you convergence that you give it will just
stop there so let's just calculate that basically what it does is yeah it gives
you the values that you said on the residuals plot because we said that
and it's just doing the simulation
so once we've finished the simulation what we do is we export the data so that we
can view it on cfd post so cfd post is the platform where we can see our
results so if you pick this and you pick wherever results that you wanna look at
and you can pick whatever parameters so maybe in this case I'll pick pressure
and velocity and then just write the file same thing what directory and
then click OK and that's when you have written your CFD post files
so in CFD post remember the file that we've written so now let's just load the
results that we have in CFD post so go back to the directory that you set and
pick the file that's compatible for CFD post and click open and just click OK
and you should tick this button you will be able to see the different parts of
the geometry right so let's say if I want to look at a contour plot of the
pressure I'll just set contour plot all domains
fistula wall pressure depends on what contour plot maybe 100 click apply
yeah so then you can see I'm the pressure contour of your geometry yeah
you can play with different different contrast band transparency so once you look
at your contour plot there's also different things that you can look at so
like streamline particle track if you're looking at multi-faced analysis or
you know vector plots and stuff like that so that's where you can look at
your results if you wanna save results you can click this save results button
figure if you wanna look at a chart, you can click the chart just so that you can
look at different parameters how it differs accross maybe the central line or
stuff like that so it gives you a different ways to do it
alternatively you can always export the data to MATLAB or Excel that helps you
plot better graphs so it's really up to you and CFD Post gives you just the
visualization of your results in CFD