2D transient analysis for heat conduction

In summary, the conversation discusses the request for a fem code in MATLAB or Fortran, which is deemed unethical and unfair to others who have completed the work on their own. The original poster then asks for clarification on where they are stuck, leading to a discussion on the trapezoidal rule and the use of boundary conditions in the solution. The conversation then shifts to a question about the calculation of V for different nodes and the precedence of prescribed flux values on adjacent boundaries.
  • #1
nellierd
11
0
I need a fem code either in MATLAB or fortran to refer to as I am stuck at some places. Please help.
 
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  • #2
Simply giving you a code for your homework (probably a final project even) would be quite unethical...more importantly though it wouldn't be fair to those of us who did it by ourselves.

Perhaps you can shed some light on where you're stuck. No one is going to do your work fro you.
 
  • #3
I love these threads that start out with a completely open ended question, without any indication as to what the problem actually involves. Then they ask for all the computer code and show no work at all.

The fact that gets me, is that these posters actually think this forum is intended for this type of help.

LOL

Matt
 
  • #4
I wish I had like a 2000 line code with several modules, dozens of subroutines and such that in the end just:
Code: 
Hello World!

Hell, I'd zip it up and make sure it was always hosted.
 
  • #5
Hey, enough of criticism. Its not that if you give a code, it will be terrible. I know that I need to do my own code, which I am doing. Even if you give me a code, first I need to understand your code to implement it, which for sure won't be easy. Everybody has his/her own way of coding. Neways , my bad. I will explain where I am stuck.
When you solve a transient problem of the format.

If you have M du/dt+K u=F, we can break it into Mv(1)+K(u1)-F(1)=0 at t=t1 and
Mv(0)+K(u0)-F(0)=0. Using the trapezoidal rule, it asks to guess the V vector at t1 even though its a linear problem. I am very confused with the approach.
 
  • #6
Why did you ask for a FEM (finite element code) when you are told to use the trapezoidal rule?

The trapezoidal rule is nothing more than a numerical integration algorithm. Albeit a very robust one.

Hey, enough of criticism.

If your going to post a silly question then get ready for the criticism. When you post questions here act as if you are asking your supervisor the question. Then ask yourself the following questions.

1. Have I specified enough information so that someone can actually help me?
2. Is there any additional information that I can post that will help the person(s) trying to help me?
3. Is the spelling/grammer correct to the best of my knowledge?
4. Have I searched the forum for a similar question?
5. Is there a graph/picture that I can attach to help with the visualization of the problem?

Remember, we are not in the class with you, so make it easy for us to help you.

Thanks
Matt
 
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  • #7
Thanks. It is a numerical technique to match in time.right? Let's say I have formed my mass matrix and my element matrix. If I know the initial boundary conditions, let's say primary as well as secondary boundary conditions. When we solve MV(0)+KU(0)-F(0)=0 for V(0), where V(0) is the velocity at time t=0 and U(0) being the displacement. Do we impose the secondary boundary conditions like stresses in our F(0) vector and also the given displacements in our U vector. I am getting confused as if the primary value i.e U is known at certain nodes, V should be zero. About the secondary boundary conditions(du/dx or du/dy)...do I impose them too? If I am calculating V for time t=0 using that equation, my question is if I am calculating V for all nodes? or the interior nodes? or the nodes where only the primary value is given?
 
  • #8
Ugh.
 
  • #9
Brian_C said:
Ugh.
@Brian, y was your response like this? Was my question so annoying?
 
  • #10
Nobody has any idea what you're talking about. The title of the thread mentions heat transfer, but it looks like you're solving some kind of structural dynamics problem.
 
  • #11
Brian_C said:
Nobody has any idea what you're talking about. The title of the thread mentions heat transfer, but it looks like you're solving some kind of structural dynamics problem.

Let me rephrase the question in terms of temperature.
When we solve MV(0)+KU(0)-F(0)=0 for V(0), where V(0) is the dT/dt at time t=0 and U(0) being the temperature. Do we impose the secondary boundary conditions like flux in our F(0) vector and also the given temperatures in our U vector. I am getting confused as if the primary value i.e U is known at certain nodes, V should be zero. About the secondary boundary conditions(du/dx or du/dy)...do I impose them too? If I am calculating V for time t=0 using that equation, my question is if I am calculating V for all nodes? or the interior nodes? or the nodes where only the primary value is given?
Hopefully, this might be clearer.

Also if on two boundaries ,adjacent ones, fluxes are prescribed on both of them, which one takes precedence? for example , one boundary has flux given 10 and another 100. The node common to both these boundaries will take what value of flux?
 

FAQ: 2D transient analysis for heat conduction

What is 2D transient analysis for heat conduction?

2D transient analysis for heat conduction is a mathematical and computational method used to study the transfer of heat through a two-dimensional object or system over time. It takes into account factors such as temperature, thermal conductivity, and boundary conditions to model the flow of heat and predict how it will change over time.

Why is 2D transient analysis important in scientific research?

2D transient analysis is important because it allows scientists to accurately model and understand the behavior of heat in various systems. This information is crucial in many fields, such as materials science, engineering, and environmental science, as it helps in the design and optimization of structures and processes.

What are the key parameters used in 2D transient analysis for heat conduction?

The key parameters used in 2D transient analysis for heat conduction include thermal conductivity, specific heat, density, boundary conditions, and initial conditions. These parameters are used to define the material properties and environmental factors that affect the flow of heat in the system.

How is 2D transient analysis different from 1D and 3D analysis?

2D transient analysis differs from 1D and 3D analysis in that it takes into account heat transfer in two dimensions, rather than just one or three. This allows for a more comprehensive understanding of the system's behavior, as it considers heat flow in both the x and y directions.

What are some applications of 2D transient analysis for heat conduction?

2D transient analysis for heat conduction has many practical applications, such as predicting the thermal behavior of electronic devices, studying the effects of heat on building materials, and analyzing the cooling of hot fluids in industrial processes. It is also used in research to better understand geothermal systems, climate change, and other natural phenomena.

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