Hot-Wire Techniques for the Determination of the Reynolds Stress Tensor in Three-Dimensional Flows

Artikel i vetenskaplig tidskrift, 1986

Increasing demands on performance and economy of aeroplanes, cars and ships well as turbomachines require a physical understanding of complex three-dimensional turbulent flow fields. Further, the development of aerodynamics computer methods and increasing capacity of modern computers imply that flow calculations have now changed from beginning based on two dimensional data to consider the complete three-dimensional flow field. Therefore, an accurate knowledge of the three-dimensional flow field has become an essential part of modern design. The important of three-dimensional turbulent flows was pointed out by Prandtl, but the first worked in this field was published in 1935 by Gruschwitz [1], who measured the mean flow field of the flat end wall of a curved two dimensional duct. Another major work in the field of three-dimensional turbulent boundary layers was published just after the Second World War by Kuethe [2], who investigated the boundary layer of a yawed wing. In the fifties, the number of investigations published was fairly limited and as late as in 1960 only 15 different experiments were reported. However, an increasing interest in the field of three-dimensional flows was initiated in the sixties, and at the end of the decade, 1969, Bradshaw and Terrel [3] reported the first investigations in which the Reynolds stresses were determined. The objectives of the present paper is to describe different hot-wire techniques available for the measurement of three dimensional turbulence flow fields, and to form a base from which the most suitable method for a certain flow case could be chosen.