Doubts in catalytic convertor tutorial

kish · September 7, 2013, 08:06

Dear all

I have question in the catalytic converter tutorial.
In the Global initialization tab they have introduced w= -2.8 m/s.
Why in the tutorial the negative sign has been introduced instead of 2.8 m/s?

I Need your help

Thank you

ghorrocks · September 8, 2013, 07:29

Because the flow is in the negative w direction. Isn't that obvious?

kish · September 8, 2013, 12:03

Quote:

Originally Posted by ghorrocks

Because the flow is in the negative w direction. Isn't that obvious?

If you are saying flow is in the negative w direction then input velocity may be negative sign (-25 m/s). then why the normal speed will be positive 25m/s ? is the normal speed means modulus of the velocity?

Thank you

Regards

ghorrocks · September 8, 2013, 20:33

When you define velocity at an inlet you just specify the magnitude. But for the initial condition you specify the full velocity vector. Hence the initial conditions is w=-2.8m/s, but the inlet is as positive number.

kish · September 10, 2013, 12:16

Quote:

Originally Posted by ghorrocks

When you define velocity at an inlet you just specify the magnitude. But for the initial condition you specify the full velocity vector. Hence the initial conditions is w=-2.8m/s, but the inlet is as positive number.

It is very useful

Thank you so much

September 7, 2013, 08:06	Doubts in catalytic convertor tutorial	#1
kish New Member Kishore Join Date: Mar 2013 Posts: 20 Rep Power: 13	Dear all I have question in the catalytic converter tutorial. In the Global initialization tab they have introduced w= -2.8 m/s. Why in the tutorial the negative sign has been introduced instead of 2.8 m/s? I Need your help Thank you

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September 8, 2013, 07:29		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	Because the flow is in the negative w direction. Isn't that obvious?

September 8, 2013, 20:33		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	When you define velocity at an inlet you just specify the magnitude. But for the initial condition you specify the full velocity vector. Hence the initial conditions is w=-2.8m/s, but the inlet is as positive number.