RF/Microwave Engineering and Applications in Energy Systems. Abdullah Eroglu
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СКАЧАТЬ due to interior surfaces is zero. The contributions that are nonzero occur only for the surfaces enclosing the outer surface of the volume.

Schematic illustration of divergence theorem.

      Verify the divergence theorem for vector

      (1.68)upper T overbar equals x ModifyingAbove x With ampersand c period circ semicolon plus y ModifyingAbove y With ampersand c period circ semicolon plus z ModifyingAbove z With ampersand c period circ semicolon

      Solution

      (1.70a)normal d s overbar Subscript 1 Baseline equals minus ModifyingAbove z With ampersand c period circ semicolon italic dxdy

      (1.70b)normal d s overbar Subscript 2 Baseline equals minus ModifyingAbove y With ampersand c period circ semicolon italic dxdz

      (1.70c)normal d s overbar Subscript 3 Baseline equals minus ModifyingAbove x With ampersand c period circ semicolon italic dydz

      To be able to find the differential surface area vector normal d s overbar Subscript 4 for surface 4, we need to determine the normal vector for that surface. The normal vector can be found using the equation

Schematic illustration of geometry of Example 1.4.

      (1.73)upper C equals x plus upper A left-parenthesis 0 right-parenthesis plus upper B left-parenthesis 0 right-parenthesis right double arrow upper C equals a

      Similarly, from intercept point (0,b,0)

      (1.74)a equals left-parenthesis 0 right-parenthesis plus upper A left-parenthesis b right-parenthesis plus upper B left-parenthesis 0 right-parenthesis right double arrow upper A equals StartFraction a Over b EndFraction

      and from intercept point (0,0,c)

      (1.75)a equals x left-parenthesis 0 right-parenthesis plus upper A left-parenthesis 0 right-parenthesis plus upper B left-parenthesis c right-parenthesis right double arrow upper B equals StartFraction a Over c EndFraction

      Then, function f is defined by

      (1.77)ModifyingAbove n With ampersand c period circ semicolon equals StartFraction nabla f Over StartAbsoluteValue nabla f EndAbsoluteValue EndFraction equals StartStartFraction ModifyingAbove x With ampersand c period circ semicolon plus StartFraction a Over b EndFraction ModifyingAbove y With ampersand c period circ semicolon plus StartFraction a Over c EndFraction ModifyingAbove z With ampersand c period circ semicolon OverOver StartRoot 1 plus left-parenthesis StartFraction a Over b EndFraction right-parenthesis squared plus left-parenthesis StartFraction a Over c EndFraction right-parenthesis squared EndRoot EndEndFraction

      We can then calculate the surface area as

      where