Hal Murray wrote: > p...@phk.freebsd.dk said: > >>> Can I get reflections without some inductance? >>> Is there any inductance in a system of alternating >>> layers of insulation/storage? >>> > > >> I think you are overstretching the badly chosen nomenclatures >> parallels to electricity. >> > > It was actually a (somewhat?) serious question on several grounds. > > Can I get reflections from a lumped circuit model of a transmission line made > out of just Rs and Cs? If so, I can probably do the same in the thermal > world. > > Can I get reflections in a thermal context? Bruce's URLs say yes, but my > math is rusty enough that I can't quickly understand what's going on. > > If a thermal problem can generate reflections, does that mean it also has > something corresponding to inductance? If so, what is it? > > It's possible that the key idea is time-delay. In the electrical world, a > delay is a transmission line which has both C and L. I'm not sure what the > one-dimensional equivalent in the thermal world is. > > What's the speed-of-light equivalent in the thermal world? > > > > > > Hal
Thermal wave group velocity = 2*SQRT(4*PI*(thermal diffusivity)/(thermal wave period)). for a derivation see: http://books.google.co.nz/books?id=qSyAKzgwedIC&pg=PA153&lpg=PA153&dq=thermal+wave+velocity+diffusivity&source=bl&ots=95aUo2w5Ho&sig=t5seHCNo7H_RacyFUPcn6NFS2q0&hl=en&ei=DG0wSo-zGZ2MtgPX79C-Aw&sa=X&oi=book_result&ct=result&resnum=8#PPA153,M1 <http://books.google.co.nz/books?id=qSyAKzgwedIC&pg=PA153&lpg=PA153&dq=thermal+wave+velocity+diffusivity&source=bl&ots=95aUo2w5Ho&sig=t5seHCNo7H_RacyFUPcn6NFS2q0&hl=en&ei=DG0wSo-zGZ2MtgPX79C-Aw&sa=X&oi=book_result&ct=result&resnum=8#PPA153,M1> pages 153 -154 Note there is dispersion - the propagation velocity depends on the period of the thermal wave. Bruce _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.