WUF.NICVlm II new book on compres~ible-Huid dynamics appears t·here i~ always a tendency to compare it. wit.h the weIlknown works by Shapiro and hy Liepmanll and Hoshko. Although t.hcse hooks have dominat.ed t.his area for many years, there has heen a growing need recently for a new text. OIl compressihle flows suit.ahle for use at t.he senior and first.-year grad1lI,te level. It is the opinion of this reviewer that I.hi,; book fiIlH t.his need admirably.The hook is qui\(! 10llg, and contains far moJ'(! material t.han ean be ilworporated into a single comse. There arc I I chapters in all, t.llI! first two of which present. all introduetion t.o Huid merhanics alHI t.hermodynumics. This mat.erial rould form t.llI! basis of an introduct.ory course on the foundat.iuns of fluid mcchani(!s probably a), t.he first-year graduale level. The lhird chapt.er ronsist.s of an introduction t.o dimensional analysis and similarit.y. The rompressihle-flow IIlRterial st.ltrl~ It!. Clmpter four wit.h a rather lengt.hy ehapt.er on physical llrollst.ies. The author t.reat.~ aeollst.ics from a Hlliri mechanics point of view, and the mat erial rOllld ea~ily form t.hl! basis for the first. part. of an int.roductory course Oil acollsLirs. There follows an interest.ing little chaptnr 011 the nat.ure of steady compressihle flows, after whieh t.he famili:1l' topies of olw-dimensional and two-riimensional st.eady flows, shock waves, and one-(Iimensional unst.l!ariy flows arc discuHsed. FOllr specific examples of self-similar motions arc c1e~crihed in 1\ clmpter under t.hRt hellding, Imd t.he finIlI chapt.er on analogs in compressihle flow inclndes, among ot.hers, shallow WIlt.er waves and t.raffic flow.The hook is very well writ.ten and illnstrated, and contains II conHiderahle nnmber of relevanl problems t.o be worked hy t.he reader. The main emphasis is claimeri to be on fundamentals, hut there is no short.age of good illustmt.ive examples. An ellgaging feRt,ure of the book is t.he illelusioll of short hi"torical remarks which arc scat. Although t.he aut.hors stat.ed in the Int.roduct.ion that. t.he reader of t.he book is "to be equipJled wit.h a· normal undergraduat.e haggage of Ilwr:hanics, applil!ll mat.lwllIatir:s, and strlldmal engineering," the level of eontents of t.his hook is far n,bove wlmt. an ordinllry graduat(! in engineering, even wit.h arlvtlnc(!(1 riegrees, ean comprehend. 1-linee the suhjects of linear anel nonlinear vibl'll(.ions, eIIlst.ir: waves, probabilit.y and st.at.istirs, opt.imi"ations, ami theory of st.rudllres nil have import.ant applieations in Earthquake Engineering, applieri mechanicians, who are well grounderi on t1l1!se suhjerls, lIlay finel t.his hook ext.remely int.erest.ing. 'Professor,

The quantity which is here called the fundamental derivative has been defined as the nondimensional form Γ≡12ρ3c4(∂2Υ/∂P2)s. The relation of Γ to other thermodynamic variables is discussed. It is already known that the existence of conventional compression shocks requires Γ>0. It is shown that other dynamic behavior of compressible fluids is fixed by the sign of Γ. Particular emphasis is given to phenomena corresponding to negative Γ. These phenomena include the area variation of a transonic passage, the form of a Prandtl-Meyer wave, the behavior of adiabatic flow with friction, and nonlinear wave propagation. Formulas and numerical values are given for Γ in various substances.

No abstract

Negative or rarefaction shock waves may exist in single-phase fluids under certain conditions. It is necessary that a particular fluid thermodynamic quantity Γ ≡ −½δ In (δP/δν)s/δ In ν be negative: this condition appears to be met for sufficiently large specific heat, corresponding to a sufficient level of molecular complexity. The dynamic formation and evolution of a negative shock is treated, as well as its properties. Such shocks satisfy stability conditions and have a positive, though small, entropy jump. The viscous shock structure is found from an approximate continuum model. Possible experimental difficulties in the laboratory production of negative shocks are briefly discussed.

The emergence of a shockwave from the open end of a shock tube is studied, with special emphasis on test fluids of high molar heat capacity, i.e. retrograde fluids. A variety of wavelike vapour-liquid phase changes are observed in such fluids, including the liquefaction shock, mixture-evaporation shock, condensation waves associated with shock splitting and liquid-evaporation waves (these phenomena have analogues in the polymorphic phase changes of solids; only the first two are treated in this paper). The open end of the shock-tube test section discharges into an observation chamber where photographs of the emerging flow are taken. Calculations were performed with the Benedict-Webb-Rubin, van der Waals and other equations of state. Numerical (finite-difference) predictions of the flow were made for single-phase and two-phase flows: solutions were tested against the experimental shock diffraction and vortex data of Skews. The phase-change properties of the test fluid can be quantified by the ‘retrogradicity’ r(T), measuring the difference in slope between the P, T isentrope and the vapour-pressure curve, and the ‘kink’ k(T), measuring the difference between the single-phase and mixture sound speeds. Mixture-evaporation (i.e. rarefaction) shocks appear to have a sonic-sonic or double Chapman-Jouguet structure and show agreement with amplitude predictions based on k(T). Liquefaction shocks are found to show a reproducible transition from regular, smooth shock fronts to irregular, chaotic shock fronts with increasing shock Mach number. This transition can be correlated with published stability limits.