Heat Conduction vs. One-Dimensional Wave Equation Conduction and...Microsoft Word - Heat Conduction...

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Heat Conduction and One-Dimensional Wave Equations ∝ !! = ! vs. α !! = !! Heat Conduction: ∝ ! !! = ! Boundary conditions: (0, ) = 0, (, ) = 0 Case: Bar with both ends kept at 0 degree General Solution: , = ! ! !!! !∝ ! ! ! ! ! !/! ! !"# ! Steady State Solution: () = 0 Other info: ! = ! = 2 ! ! Heat Conduction: ∝ ! !! = ! Boundary conditions: ! (0, ) = 0, ! (, ) = 0 Case: Bar with both ends perfectly insulated General Solution: , = ! + ! ! !!! !∝ ! ! ! ! ! !/! ! !"# ! Steady State Solution: () = ! Other info: ! = ! ! ! ! = ! = 2 ! !

Transcript of Heat Conduction vs. One-Dimensional Wave Equation Conduction and...Microsoft Word - Heat Conduction...

Page 1: Heat Conduction vs. One-Dimensional Wave Equation Conduction and...Microsoft Word - Heat Conduction vs. One-Dimensional Wave Equation.docx Author Michael James Omelchenko Created Date

Heat Conduction and One-Dimensional Wave Equations ∝𝟐 𝑒!! = 𝑒! vs. Ξ±πŸπ‘’!! = 𝑒!!

Heat Conduction: ∝! 𝑒!! = 𝑒!

Boundary conditions: 𝑒(0, 𝑑) = 0,𝑒(𝐿, 𝑑) = 0

Case: Bar with both ends kept at 0 degree General Solution: 𝑒 π‘₯, 𝑑 = 𝐢!!

!!! 𝑒!∝!!!!!!/!!𝑠𝑖𝑛 !"#

!

Steady State Solution: 𝑣(π‘₯) = 0 Other info:  

𝐢! = 𝑏! =2𝐿

𝑓 π‘₯ π‘ π‘–π‘›π‘›πœ‹π‘₯𝐿𝑑π‘₯

!

!

Heat Conduction: ∝! 𝑒!! = 𝑒!

Boundary conditions: 𝑒!(0, 𝑑)  =  0,𝑒!(𝐿, 𝑑)  =  0

Case: Bar with both ends perfectly insulated General Solution: 𝑒 π‘₯, 𝑑 = 𝐢! + 𝐢!!

!!! 𝑒!∝!!!!!!/!!π‘π‘œπ‘  !"#

!

Steady State Solution: 𝑣(π‘₯) = 𝐢! Other info: 𝐢! =

!!!

𝐢! = π‘Ž! =2𝐿

𝑓 π‘₯ π‘π‘œπ‘ π‘›πœ‹π‘₯𝐿𝑑π‘₯

!

!

Page 2: Heat Conduction vs. One-Dimensional Wave Equation Conduction and...Microsoft Word - Heat Conduction vs. One-Dimensional Wave Equation.docx Author Michael James Omelchenko Created Date

Heat Conduction: ∝! 𝑒!! = 𝑒!

Boundary conditions: 𝑒 0, 𝑑 = 𝑇!,𝑒 𝐿, 𝑑 = 𝑇!

Case: Bar with 𝑇! degrees at the left end, and 𝑇!degrees at the right end General Solution: 𝑒 π‘₯, 𝑑 = !!!!!

!π‘₯ + 𝑇! + 𝐢!!

!!! 𝑒!∝!!!!!!/!!𝑠𝑖𝑛 !"#

!

Steady State Solution: 𝑣 π‘₯ = !!!!!

!π‘₯ + 𝑇!

Other info: 𝑣(π‘₯) = 𝐴π‘₯ + 𝐡 , and 𝑀 π‘₯, 0 = 𝑓 π‘₯ βˆ’ 𝑣(π‘₯)

𝐢! = 𝑏! =2𝐿

(𝑓 π‘₯ βˆ’ 𝑣 π‘₯ )π‘ π‘–π‘›π‘›πœ‹π‘₯𝐿𝑑π‘₯

!

!

One-Dimensional Wave Equations: Ξ±!𝑒!! = 𝑒!!

Boundary conditions: 𝑒 0, 𝑑 = 0,𝑒 𝐿, 𝑑 =  0

Initial conditions: 𝑒(π‘₯, 0) = 𝑓(π‘₯),𝑒!(π‘₯, 0) = 𝑔(π‘₯)

Case: Undamped One-dimensional Wave Equation General Solution: 𝑒 π‘₯, 𝑑 = (𝐴!!

!!! π‘π‘œπ‘  !"#$!+ 𝐡!𝑠𝑖𝑛

!"#$!)𝑠𝑖𝑛 !"#

!

Other info: ** See Special Cases Below **  

𝐴! = 𝑏! =2𝐿

𝑓 π‘₯ π‘ π‘–π‘›π‘›πœ‹π‘₯𝐿𝑑π‘₯

!

!

𝐡! =πΏπ‘Žπ‘›πœ‹

𝑏! =2π‘Žπ‘›πœ‹

𝑔 π‘₯ π‘ π‘–π‘›π‘›πœ‹π‘₯𝐿𝑑π‘₯

!

!

Page 3: Heat Conduction vs. One-Dimensional Wave Equation Conduction and...Microsoft Word - Heat Conduction vs. One-Dimensional Wave Equation.docx Author Michael James Omelchenko Created Date

One-Dimensional Wave Equations: Ξ±!𝑒!! = 𝑒!!

Boundary conditions: 𝑒 0, 𝑑 = 0,𝑒 𝐿, 𝑑 =  0

Initial conditions: 𝑒 π‘₯, 0 = 0  ,𝑒!(π‘₯, 0) = 𝑔(π‘₯)

Case: Special Case of Undamped One-dimensional Wave Equation π‘–π‘›π‘–π‘‘π‘–π‘Žπ‘™  π‘‘π‘–π‘ π‘π‘™π‘Žπ‘π‘’π‘šπ‘’π‘›π‘‘ = 0 General Solution: 𝑒 π‘₯, 𝑑 = (𝐡!𝑠𝑖𝑛

!"#$!)𝑠𝑖𝑛 !"#

!

Other info: 𝐴! = 0

𝐡! =πΏπ‘Žπ‘›πœ‹

𝑏! =2π‘Žπ‘›πœ‹

𝑔 π‘₯ π‘ π‘–π‘›π‘›πœ‹π‘₯𝐿𝑑π‘₯

!

!

One-Dimensional Wave Equations: Ξ±!𝑒!! = 𝑒!!

Boundary conditions: 𝑒 0, 𝑑 = 0,𝑒 𝐿, 𝑑 =  0

Initial conditions: 𝑒(π‘₯, 0) = 𝑓(π‘₯),𝑒!(π‘₯, 0) = 0

Case: Special Case of Undamped One-dimensional Wave Equation π‘–π‘›π‘–π‘‘π‘–π‘Žπ‘™  π‘£π‘’π‘™π‘œπ‘π‘–π‘‘𝑦 = 0 General Solution: 𝑒 π‘₯, 𝑑 = (𝐴!!

!!! π‘π‘œπ‘  !"#$!)𝑠𝑖𝑛 !"#

!

Other info: 𝐡! = 0  

𝐴! = 𝑏! =2𝐿

𝑓 π‘₯ π‘ π‘–π‘›π‘›πœ‹π‘₯𝐿𝑑π‘₯

!

!

𝐡! = 0