Obtrusions such as bends, constrictions and junctions occurring in confined flows give rise to turbulent flow structures and separation zones. The acoustic analysis of the flow-induced noise may be accomplished using two different approaches. The first is the highest modeling approach, wherein the full set of compressible Navier Stokes equations is solved. Difficulties lie in the amplitude disp...

The sound generated by viscous ow past a circular cylinder is predicted via the Lighthill acoustic analogy approach. The two dimensional ow eld is predicted using two unsteady Reynolds-averaged Navier-Stokes solvers. Flow eld computations are made for laminar ow at three Reynolds numbers (Re = 1000, Re = 10; 000, and Re = 90; 000) and two di erent turbulent models at Re = 90; 000. The unsteady ...

We introduce and study a toy model which captures some essential features of wave radiation by slow (or balanced) motion in the atmosphere and the ocean. Inspired by the widely studied five-component model due to Lorenz, the model describes the coupling of a nonlinear pendulum with linear waves. The waves obey a one-dimensional linear Klein–Gordon equation, so their dispersion relation is ident...

Recently, Berthelin et al [5] introduced a traffic flow model describing the formation and the dynamics of traffic jams. This model which consists of a Constrained Pressureless Gas Dynamics system assumes that the maximal density constraint is independent of the velocity. However, in practice, the distribution of vehicles on a highway depends on their velocity. In this paper we propose a more r...

This paper further investigates the specification and calibration of FDs. The purpose is to provide a consistent, systematic, and adaptive way to obtain FDs from single-loop detector measurements. In particular, the piecewise linear form is adopted for the FD, because (a) more-complex forms of the FD can be approximated by a piecewise linear form with arbitrarily many pieces, and (b) empirical ...

W this biblical beginning, I started a paper in 1974 reviewing the development of traffic control theories. I think it is appropriate to start the present paper the same way. Traffic problems existed, to some extent, even before the Ford, which ushered the age of universal automobile transportation. But the problems were relatively small and isolated, and did not provoke much thought for their ...