On the possible origin of a vapour cone occurring during the transonic flight in moist air

¹ Technical University of Liberec, Studentská 1402/2, 461 17, Liberec, Czech Republic
² Institute of Thermomechanics of the Czech Academy of Sciences, Dolejškova 1402/5, 182 00, Prague 8, Czech Republic
³ Czech Technical University in Prague, Faculty of Mechanical Engineering, Technická 4, 166 07, Prague 6, Czech Republic

^* e-mail: hala@it.cas.cz

Published online: 24 October 2022

Abstract

In aerodynamics as in other sciences, there are some phenomena which are widely explained in a way that under a closer look turns out to be based on wrong assumptions and thus not very convincing. One of these is the effect referred to as vapour cone or shock collar which is the cloud of condensed water of the conical shape that forms around objects travelling at transonic speeds through the moist air. This paper aims to shed light on some basic principles that might stand behind this effect and based on the simple physical model provide possible explanation and correct some of the common misconceptions which are repeated ad nauseam not only on the internet sites of aerodynamics enthusiasts but also in some textbooks.