Der BeschluB des Generalrats der Internationalen Union fill Theo retische und Angewandte Mechanik (IUTAM), ein Symposium tiber Grenzschichtforschung vorzubereiten, war von dem Wunsch getragen, Wissenschaftlern aus aller Welt, die in eigenen Arbeiten zu den neueren Fortschritten auf diesem wichtigen Gebiet der Stromungsmechanik wesentlich beigetragen haben, zu grtindlichen Diskussionen Gelegenheit zu geben. Die grundsatzlichen Probleme der Grenzschichtforschung soUten bei der Aussprache im V ordergrund stehen, die technischen An wendungen muBten im Hintergrund bleiben. Da eine echte Diskussion nur in einem relativ kleinen Kreis moglich ist, hat das Wissenschaftliche Komitee den Kreis der Teilnehmer be schrankt, dabei aber nach Moglichkeit Vertreter aus allen an den Fort schritten der Grenzschichtforschung beteiligten Nationen zusammenge fUhrt. Die Teilnehmer wurden in Beratungen des Wissenschaftlichen Komitees ausgewahlt und entweder zur Erstattung eines allgemeinen oder eines speziellen Berichtes eingeladen bzw. zur Teilnahme an den Diskussionsveranstaltungen aufgefordert. Das Ergebnis dieser Tagung legen wir hiermit vor. 1m Druck sind aIle jene Fragen und Bemerkungen aus den Diskussionen weggelassen wor den, die sich durch das V orliegen des voUen V ortragstextes in diesem Buch von selbst erledigen, bzw. die durch nachtragliche Bearbeitung des Manuskriptes von den Autoren beriicksichtigt worden sind. Wir empfinden es mit Dank als eine Ehrung, daB die erste Veranstal tung der IUTAM in Deutschland die Grenzschichtforschung behandelt und damit das Gedenken an LUDWIG PRANDTL wachhalt, den Begriinder der Grenzschichtforschung und den Forderer der modernen Stromungs forschung.

Boundary Layer and Flow Control: Its Principles and Application, Volume 2 focuses on the layer of fluid in the immediate area of a bounding surface where the effects of viscosity are substantial. This book is organized into two main topics—boundary layer control for low drag, and shock-induced separation and its prevention by design and boundary layer control. It specifically discusses the nature of transition, effect of two-dimensional and isolated roughness on laminar flow, and progress in the design of low drag aerofoils. The onset of separation effects for aerofoils and wings, shock-induced separation for laminar boundary layers, and shock-induced separation for laminar boundary layers are also deliberated. This volume is recommended to physicists and specialists interested in boundary layer and flow control.

343 Whilst this may be so it is also true that this in itself is not sufficient to deter mine it completely. In fact the extent of the dead air region and the behaviour of the shear layer are also of prime importance and in short a unified treatment comprising external flow, boundary layer, shear layer and dead air region becomes necessary to complete the investigation. This would take us outside the scope of the present article and for the substantial progress that has been made towards such a treatment the reader is referred to a paper by HOLDER and GADD 1 and its comprehensive list of references. v. Heat transfer in incompressible boundary layers. 25. Introduction. The term fluid includes gases and liquids. Both gases and liquids are to some extent compressible but in many problems of fluid flow the density changes occurring are small. When they are small enough to be negligible we can regard the flow as incompressible. In Chap. IV we have established the equations for compressible flow of gases and these can of course be used to deter mine when density changes in a gas flow are in fact negligible. Broadly speaking this will be so when the temperature changes as determined by the energy equation are small enough.

A new edition of the almost legendary textbook by Schlichting completely revised by Klaus Gersten is now available. This book presents a comprehensive overview of boundary-layer theory and its application to all areas of fluid mechanics, with emphasis on the flow past bodies (e.g. aircraft aerodynamics). It contains the latest knowledge of the subject based on a thorough review of the literature over the past 15 years. Yet again, it will be an indispensable source of inexhaustible information for students of fluid mechanics and engineers alike.

After conclusion of the spin investigation of the model ME 210 with elongated fuselage and central vertical tail surfaces (model condition III; reference 3), tests were performed on the same model with a vee tail (model condition IV). Here the entire tail surfaces consist of only one surface with pronounced dihedral. Since the blanketing of the vertical tail surfaces by the horizontal tail surfaces, which may occur in case of standard tail surfaces, does not occur here, one could expect for this type of tail surface favorable spin characteristics, particularly with respect to rudder effectiveness for spin recovery. However, the test results did not confirm these expectations. The steady spin was shown to be very irregular; regarding rudder effectiveness the vee tail surfaces proved to be inferior even to standard tail surfaces, thus they represent the most unfavorable of the four fuselage and tail-surface combinations investigated so far.

Chiefly translations from foreign aeronautical journals.