Steady State Vs Transient answers

vigneshz259 · May 9, 2017, 05:57

I'm doing thermal analysis of heat sink with three module .in the cabinet two side opening one side is min value & other side is max value. minimum side i'm giving 10m/s velocity. Three module wattage respectively 150w,90w,60w.
Heat transfer coefficient is 10w/k.m.I'm new to analysis filed .what if ask boundary condition means what should i say.

Please answer me clearly.

ghorrocks · May 9, 2017, 08:45

ANSYS Icepak does not have a forum for it - the fluent one may be more appropriate but I suspect not very useful.

But an overall comment: What heat transfer coefficient are you talking about? On the surface of the heat sink, or of the whole heat sink assembly?

vigneshz259 · May 9, 2017, 11:46

For whole assembly. and also please explain to me what is convergence criteria.and difference between steady state thermal analysis & transient analysi.

ghorrocks · May 9, 2017, 19:25

This is basic CFD modelling stuff - you need to do the tutorial examples and read the documentation to understand the basics. I am not going to rewrite a textbook in a forum post to explain basic concepts like that (sorry).

guohanqing · July 23, 2017, 03:20

Hello,
When I was simulating a propeller in CFX, I used both steady and transient method, however the lift in transient is 10% higher than in steady method. I don't know why that great differences happened. Can anyone help explain that. The physical timescale in steady method is T*1/180。the time step in transient calculation is also T*1/180.

ghorrocks · July 23, 2017, 04:20

Inaccurate simulation results can be caused by many things. Have a look in the FAQ page for the Ansys wiki on fd-online.

May 9, 2017, 05:57	Can any tell me please what is the boundary condition in ansys icepak.	#21
vigneshz259 New Member Vignesh A Join Date: May 2017 Location: Indore ,Madhya Pradesh ,India Posts: 5 Rep Power: 9	I'm doing thermal analysis of heat sink with three module .in the cabinet two side opening one side is min value & other side is max value. minimum side i'm giving 10m/s velocity. Three module wattage respectively 150w,90w,60w. Heat transfer coefficient is 10w/k.m.I'm new to analysis filed .what if ask boundary condition means what should i say. Please answer me clearly.

May 9, 2017, 08:45		#22
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,852 Rep Power: 144	ANSYS Icepak does not have a forum for it - the fluent one may be more appropriate but I suspect not very useful. But an overall comment: What heat transfer coefficient are you talking about? On the surface of the heat sink, or of the whole heat sink assembly? vigneshz259 likes this.

May 9, 2017, 11:46	ansys icepak boundary condition	#23
vigneshz259 New Member Vignesh A Join Date: May 2017 Location: Indore ,Madhya Pradesh ,India Posts: 5 Rep Power: 9	For whole assembly. and also please explain to me what is convergence criteria.and difference between steady state thermal analysis & transient analysi.

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May 9, 2017, 19:25		#24
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,852 Rep Power: 144	This is basic CFD modelling stuff - you need to do the tutorial examples and read the documentation to understand the basics. I am not going to rewrite a textbook in a forum post to explain basic concepts like that (sorry).

July 23, 2017, 03:20		#25
guohanqing New Member GUO Hanching Join Date: Jun 2016 Posts: 2 Rep Power: 0	Hello, When I was simulating a propeller in CFX, I used both steady and transient method, however the lift in transient is 10% higher than in steady method. I don't know why that great differences happened. Can anyone help explain that. The physical timescale in steady method is T1/180。the time step in transient calculation is also T1/180.

July 23, 2017, 04:20		#26
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,852 Rep Power: 144	Inaccurate simulation results can be caused by many things. Have a look in the FAQ page for the Ansys wiki on fd-online.