ANSYS FLUENT TUTORIAL : CFD Analysis of An Acoustics Louver | Turbulence and Acoustic Performance

Hello friends, welcome to Anis tutori.

In this video, we are going to simulate

an acoustical lure using anis plane.

This tutorial uses anis plane to

simulate a 2D acoustical lure to observe

the aerodynamic pressure drop and change

in velocity. And visually we are going

to observe

the sources of the selfgenerated noise

using the broadband noise source model.

So let's start.

Open the unsix workbench

and drag the fluid flow fluent into the

project schematic space. Right click on

this geometry and select new design

modeler geometry. We're going to create

the geometry using the design modeler of

the ansis workbench.

Set the units as millmter. I go to XY

plane. Click on the G-axis to make this

sketch normal to the screen. Now go to

the sketching toolbox. Select the

rectangle and draw a rectangle. Now go

to dimension. Put the dimension of this

rectangle.

Put the height as 1500 mm.

I do it as 600 mm. Now we are going to

convert this 2D sketch into a 2D

surface.

For this go to concept tab and select

surface from sketches.

Select this sketch. Click on apply.

Select the operation as adden. Then

click on generate. A 2D surface has been

generated. This is our fluid domain. Now

we are going to create the model for

this louver. For this we are going to

create a new sketch.

Select this XY plane again and insert a

new plane

and in that plane we are going to create

the profile of this louver.

Now select oval here

and draw it.

I put this dimension.

Select this point and the bottom point.

Select this point.

Select this arc.

Now we are going to select the angle.

Right click and select alternate angle.

And again select alternate angle.

put this dimensions from this vertical

axis.

Now we're going to select all this put

all these dimensions. It is 45°.

L3 is 5335 mm.

L4 is 200 mm.

L8

500 mm.

Then the radius is 20 mm.

This the Lover profile.

We're going to convert this L 2D sketch

into a 2D surface. Similarly,

select surface from sketches. Select

this sketch two and click on generate.

Now we are going to pattern this for

another two copies.

So insert a new pattern. Select this

surface body. Delete this one. Click on

apply. Then select the direction.

Click on apply. And enter the number of

copies

as two.

Offset value. Enter the offset value as

150.

And number of copies as two.

Then click on generate.

Three numbers of

lubers has been generated. We are now

going to subtract

it from this fluid domain.

For this go to create menu and select

boolean operation. Select the subtract

option.

Select the fluid domain as the target

body

and this B

ser tool bodies and preserve tool bodies

option as no. So that only fluid domain

would be remain with three Ps like this.

Now we are going to split this fluid

domain into three parts for a better

messing accuracy would be generated due

to that.

But this we are going to

insert another sketch. Select the XY

plane.

Insert another sketch.

Select the line tool and draw two lines

vertical lines like this.

Now put the dimensions.

Keep it as 400 mm.

We're going to convert this to a line

body. Just select the two sketch.

Click on apply. Then click on generate.

Now line bodies has been generated. Now

we are going to project this line body

onto this fluid domain surface.

For the select edges on the face option,

click on edges. Click on apply. Then

target body. Select the fluid domain as

the target. Then click on apply.

Then click on generate.

Now the fluid domain has been splitted

into three parts like this.

Now we are going to modify something

like this the second line so that it

would be equidistance from this louver

body.

Click on generate like this.

Now we we do not need this line body. So

we can suppress this one. We'll keep

this surface body.

Geometry is complete. Now close this

geometry and proceed for messing.

Insert

a sizing option.

Go to a selection tool. Select this.

Four vertical lines, vertical edges.

Enter the number of divisions. Enter the

number of divisions as 150.

You can also change as per your

requirement

inside another sizing. Select this

horizontal lines.

Put the number of divisions as 125.

Similarly, insert another Saging.

Select these two horizontal lines. Click

on apply and enter the number of

divisions as 150.

Insert face sizing option

which would generate mapped face missing

for this part and this part. Click on

apply.

Now click the generate mess.

Now here we are going to turn on this

adaptive sizing option

for a better mesh distribution.

Turn on this adaptive sizing option

and increase the resolution up to seven.

Then click on and add generate mess.

Insert sizing for this clover blades.

Enter the number of divisions.

Keep it as 20.

Also insert the refinement

there is smaller cells

and click on generate.

We are going to further do the

refinement to this middle section. So

increase the refinement up to two. Then

click on generate.

The cell size has

little better

sizing option.

Provide the select the all these curved

surfaces.

Click on apply. Enter the number of

divisions.

That's 10.

Then click on generate mess.

Now we are going to create the name

selection for various boundary surfaces.

Select this boundary and name it as

inlet.

Select this face and name it as outlet.

Select all these top and bottom edges

and name it as top and bottom wall.

Select the edges of this lower blades.

and name it as

Lor walls.

Now check all this name selection has

been assigned properly or not.

Now right click on this mess and select

update mess.

Now the mass cells has been linked with

the fluent sol. Now close this messing

and proceed for solver setup in anis

fluent

Select the double precision model. Click

on start.

Now go to models.

Select the turbulence K omega SST model

and click on okay.

Select the acoustics.

Select broadband noise sources. Give the

default value of this model parameter.

Now let's understand what are the

various model parameters that to be used

in aquestics model.

First model parameter is the far field

density.

Farfield density it is 1.225 kg per me

cube. is the standard density of air at

sea level.

The second parameter is farfield sound

speed. This is the speed of sound in air

medium.

Third parameter is reference acquestics

power.

Acoustics power calculations

heavily depends on the speed of sound to

relate it turbulence velocity to

acoustics pressure.

reference acostics power

that is 10 ^ minus 12 watt

which is the universally accepted

threshold of human hearing.

The fourth parameter

is number of realizations

because this model is statistical.

It guesses the noise based on the steady

turbulence rather than simulating every

sound wave.

200 iteration means that it generates

200 random turbulence samples to create

a smooth average noise prediction.

The last parameter is the number of

forer modes. This determines how the

turbulent energy is broken down into

different frequency components to

synthesize the noise mathematically.

Fifth is the standard balance between

accuracy and computational speed.

Keep the default value of acquistics

model.

Click on okay.

Now go to materials. Check the default

material as here.

Go to boundary conditions.

Select the inlet boundary.

We're going to put the inlet velocity as

5 m/s

at the inlet air velocity.

Keep the default turbulence setting

a 5% turbulent intensity.

Then go to outlet.

Keep the default pressure outlet

boundary condition.

The top and bottom walls set it as

symmetry

and click on close.

Now go to solution methods.

Select the coupled scheme

gradient as green gas cell waste.

I go to monitors residuals. Decrease the

residuals up to 10 ^ minus 6.

Click on okay.

Now go to initialation.

Do the hybrid initialization

and go to round calculation pitch. Enter

the number of iterations up to 1,000.

Put the number of iteration as 1,000.

Then click on calculate.

The iteration process should take some

time.

Calculation is complete.

Now we are going to see the aquestics

power contour. For this go to results

then contours.

Select the contours of

pressure first

to see the pressure variation in this

fluid domain.

This the pressure variation.

Now we are going to see the acostics

acquestics power level

in decibel.

Click on this display.

You can also save this contour image.

Select the resolution. Click on save.

Select

the acoustics power. Click on save

display

and select this surface acoustics power

level.

This is nearer to this blades.

Another

is surface acostics power. Now close

this contour.

Close the fluid and proceed for CFD

post-processing result analysis.

Open the CFD post processing window.

Now here we are going to insert a new

contour.

Select the location as symmetry one

variable as pressure

range as local and number of contours

100. Click on apply.

This the pressure variation contour.

You can also change this color of this

contour as per the fluent default

fluent rainbow default color.

You can modify the default legend part.

You can also save this image. Contour

image.

Again go to controls. Select the

variable as velocity.

Click on apply.

This the velocity variation.

You can also save this contour image.

You can also check the contours of

turbulence.

This specific dissipation rate,

turbulent kinetic energy.

Now turn off this contour and insert a

vector. We're going to see the velocity

vector. Select the location as symmetry

one.

Click on apply.

is the velocity vector

through the lower.

You can also save this image.

Now turn off this contour. Now insert a

new stream line. Select is at surface

trim line

and surface as the symmetry one.

Simmit one as the surface. Then click on

apply.

is the streamline variations

the path of the air traveling through

this aostic slower. With this let's

conclude this demonstration. Thank you.

Keep learning. Keep exploring.