Total thermal energy from heat equation

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SUMMARY

The discussion focuses on deriving the total thermal energy from the heat equation, specifically addressing the integral of the heat equation components. The key equation discussed is the heat equation, represented as d²u/dx² + sin(5t). The solution involves integrating the term sin(5t) over the interval from 0 to L, leading to L*sin(5t). Additionally, to find E(t), participants emphasize the importance of calculating the partial derivative with respect to time and integrating to determine the constant of integration, starting with E(0) as the integral of the initial condition.

PREREQUISITES
  • Understanding of the heat equation and its components
  • Knowledge of partial derivatives and integration techniques
  • Familiarity with boundary conditions in differential equations
  • Basic grasp of trigonometric functions and their integrals
NEXT STEPS
  • Study the derivation of the heat equation and its applications in thermal energy analysis
  • Learn about integrating trigonometric functions within boundary conditions
  • Explore methods for solving partial differential equations (PDEs) using separation of variables
  • Investigate the concept of energy conservation in thermal systems
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Students studying physics or engineering, particularly those focusing on thermodynamics and heat transfer, as well as educators seeking to enhance their understanding of the heat equation and its implications in thermal energy calculations.

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Homework Statement


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Homework Equations


Heat equation

The Attempt at a Solution


I can derive E(t) to get integral of du/dt over 0 to L, which is the same as integrating the right hand side of the original equation (d2u/dx2+sin(5t); while this allows me to take care of the d2u/dx2, I don't know what to do with the sin(5t) term or proceed from there.

Thanks.
 
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Hi, mmm ##\int_{0}^{L}\sin{5t}dx=L\sin{5t}## ...
 
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Another hint, when you find ##\frac{\partial}{\partial t} E(t)## as a function of ##t## you must integrate in order to find ##E(t)##, this gives you the problem to determine a constant of integration ... you can solve this calculating ##E(0)=\int_{0}^{L}u(x,0)dx=\int_{0}^{L}1+100\sin{\left(\frac{2\pi x}{L}\right)}dx## ...

Ssnow
 
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