Thunderhead Engineering Forum

Please login or register.

Login with username, password and session length
Advanced search  

News:

Forum moved to https://forum.thunderheadeng.com

Pages: 1 2 [3] 4 5 ... 10
 21 
 on: May 25, 2020, 04:20:31 am 
Started by alvarez.fpe - Last post by danelyoung
A StackOverflowError is simply signals that there is no more memory available. It is to the stack what an OutOfMemoryError is to the heap: it simply signals that there is no more memory available. JVM has a given memory allocated for each stack of each thread, and if an attempt to call a method happens to fill this memory, JVM throws an error. Just like it would do if you were trying to write at index N of an array of length N. No memory corruption can happen. The stack can not write into the heap.

The common cause for a stackoverflow is a bad recursive call. Typically, this is caused when your recursive functions doesn't have the correct termination condition, so it ends up calling itself forever. Or when the termination condition is fine, it can be caused by requiring too many recursive calls before fulfilling it.

Here's an example:

public class Overflow {
public static final void main(String[] args) {
main(args);
}
}

That function calls itself repeatedly with no termination condition. Consequently, the stack fills up because each call has to push a return address on the stack, but the return addresses are never popped off the stack because the function never returns, it just keeps calling itself. If the stack is full you can't push, if you do you'll get stack overflow error. StackOverflowError is avoidable if recursive calls are bounded to prevent the aggregate total of incomplete in-memory calls (in bytes) from exceeding the stack size (in bytes).


 22 
 on: May 23, 2020, 11:15:18 am 
Started by ipetrov14 - Last post by ipetrov14
After updating to the latest version Pathfinder don't start and PathfinderResults don't start. Reinstallation 2020.2.0527 does not help, previous version 2020.1 doesn't work either. List of errors in the attachment log. What to do in this case? Updating Java does not solve the problem either.
Program crashes.
 

 23 
 on: May 23, 2020, 10:23:15 am 
Started by n_moniri - Last post by Dave McGill
If you want the doors to "burn away", then you will have to have the combustion governed manually by the surface properties.

Until that happens, the room is still a sealed box. There might not be enough air in the room to support enough combustion to burn away a portion of the door.

If there is, then you need to expand the domain by a couple of meters on the side with the door on fire, and you need to put an open vent on that boundary of the domain.

I suggest you read about all of these features in the FDS Users Guide.

PyroSim recognizes that a surface has been labelled in Revit, but the surfaces created from the Revit file have no relevant properties.

 24 
 on: May 22, 2020, 03:02:36 pm 
Started by Tannazsh91 - Last post by Tannazsh91
Hi guys,
I am receiving an error during the coupling Pathfinder and Pyrosim. I have attached the error snapshot.
Any idea why this error occurs?
I was wondering if it is possible to couple 2 software tools and see the impact of fire and smoke on the decision making of agents and speed of agents by decreasing the visibility.
I appreciate any help regarding this issue.
Thank you



 25 
 on: May 22, 2020, 12:06:26 pm 
Started by n_moniri - Last post by n_moniri
Thanks Dave for your response.
By saying sealed box, you mean my model does not have any inside air flow?
If I want to address this issue I should put open vent on the wall or I should open the boundary?
When my model is imported from Revit through IFC extension to Pyrosim, does the software tool recognize that the meaning of the object? for example what is the wall or what is the door?
Thanks

 26 
 on: May 22, 2020, 05:22:25 am 
Started by n_moniri - Last post by Dave McGill
Hi,

The most obvious issue is that your domain is a sealed box.

 27 
 on: May 21, 2020, 10:13:29 pm 
Started by n_moniri - Last post by n_moniri
Hello Dave,
Thank you so much for your great and quick response.

I also have another confusion about the propagation of fire. I'm modeling a room with a wooden box in front of a door that is supposed to be burnt away. Also, I defined all the required information like materials of all the components, reaction, surfaces, and mesh.  Although I can see the smoke and the fire on the box, after 120s simulation I still can not see the propagation of fire. I attached my Pyrosim file to this post.

I would be appreciated if you help in this regard.

 28 
 on: May 21, 2020, 01:11:12 pm 
Started by n_moniri - Last post by Dave McGill
A burner can be a vent, or the face of an obstruction. It ejects fuel. With the default simple chemistry mixing model, if the fuel mixes with oxygen in the correct proportions, then combustion will occur. This is modelled on a cell-by-cell basis. No ignition source is required.

It is possible to specify an ignition temperature for a fuel or an initialization region. In those cases, a source of heat to ignite the fuel/oxygen mixture is required. That can be supplied by an ignitor, which is essentially a hot particle, placed above the source of fuel.

 29 
 on: May 21, 2020, 10:15:04 am 
Started by n_moniri - Last post by n_moniri
Dear all,
I have confusion about different possible ways for modeling fire.
As I understand, we can have a fire with a burner surface and an ignitor.
what is the difference between these two options?
Thanks

 30 
 on: May 15, 2020, 10:06:54 am 
Started by hey_youu - Last post by hey_youu
Thank you Dave! With your timely help, i completed my project on time. How i can contact you for my promise?

Pages: 1 2 [3] 4 5 ... 10