Math 252 Lecture 31: Wednesday, March 17th 1999.

We started the lecture by looking at a pattern of similarity between the Divergence Theorem, Stokes' Theorem, and Conservative Fields [Transparancy 1]. In all three cases, one of the integrals "cancels" the del operator. These are highly reminiscent of the Fundamental Theorem of Calculus, and in fact Poincaré's Lemma states that these are, in fact, higher dimensional analogues of it.

Next, we addressed a question which a student asked me at the end of last lecture, involving the application of Stokes' theorem to the divergence theorem [Transparancy 2]. This leads to an apparent contradiction. The contradiction is resolved by realizing that the divergence theorem applies to a closed surface, wheras Stokes' theorem applies to a surface bounded by a curve.

The rest of the lecture was spent on an introduction to the Transport Theorems. First, the Flux Transport Theorem was presented [Transparancy 3], followed by the Reynold's Transport Theorem, [Transparancy 4].

A second form of the Reynold's Transport Theorem was also given, making use of an expression for the convective derivative. (The convective derivative is the time rate of change of a scalar field due to two processes: an intrinsic time-dependence of the scalar field, and the velocity of the time-dependent region which is under consideration.)

A "proof" of the flux transport theorem was discussed [Transparancies 5, 6, and 7]. It involves applying the divergence theorem to the volume swept out by the time-dependent surface under consideration. (A more rigorous proof is given in Chapter 5 of the textbook, for the interested student. We won't be covering this in class.)

Here are the scanned-in transparancies, in full-colour JPEG format:

(You will find two versions -- a "screen" version, which is 400 pixels wide and a corresponding number of pixels long, at a resolution of 100 by 100 dots per inch, and a "print" version, which is generally between 8 and 8.5 inches wide and up to 11 inches long, also at a resolution of 100 by 100 dots per inch. The screen versions generally have a file size of between 70 and 95 K, which downloads reltively quickly. The print versions generally have a file size of between 170 and 240 K, which takes a bit longer to download.)


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Revised 01 April 1999 by John Hebron.