Chapter 10 - Vortex cloud modelling by the boundary integral method

Summary

Introduction

The main objective of this chapter is to present the reader with a practical numerical approach to vortex cloud modelling of bluff body flows, drawing upon the techniques developed earlier in the book and especially the treatments of vortex dynamics and viscous diffusion considered in Chapters 8 and 9. Reporting on Euromech 17, which was entirely devoted to bluff bodies and vortex shedding, Mair & Maull (1971) remarked upon the preponderance of experimental work at that time and the need for more theoretical studies to be attempted, since there was little discussion of numerical techniques. It was felt, on the other hand, that since such flows showed marked three-dimensional characteristics (e.g. a circular cylinder von Karman street wake will not in general be correlated along its length for L/D ratios in excess of 2.0), two-dimensional computations, whilst being of interest, would not be very useful. It was admitted however that ‘with an increase in the size of computers a useful three-dimensional calculation could become a reality’. By the time of the next Euromech 119 on this subject, Bearman & Graham (1979), one third of the papers focused on theoretical methods, the majority based upon the Discrete Vortex Method (DVM). Various reviews of the rapid subsequent progress with DVM were given by Clements & Maull (1975), Graham (1985a) and Roberts & Christiansen (1972) and a fairly comprehensive recent review of U.K.