This paper describes a real-time robot vision system which uses only the divergence of the optical flow field for both steering control and collision detection. The robot has wandered about the lab at 20 cm/s for as long as 26 minutes without collision.The entire system is implemented on a single ordinary UNIX workstation without the benefit of real-time operating system support. Dense optical ...

Electrically conducting fluids can generate a magnetic dynamo when layers of fluid slide past one another, often at different rates. Known as shear, this is how the Earth and the Sun produce magnetic fields. But exactly how large-scale spatial coherence over the entire surface of the Sun can arise at high magnetic Reynolds numbers, as lines of magnetic field are dragged along by fluid flow, has...

Incompressible, turbulent flow past a circular cylinder is computationally investigated by means of Reynolds Averaged Numerical Simulations. Problems in using the wall-functions approach for modeling the near-wall turbulence are demonstrated. As the main turbulence model, the Shear Stress Transport model is employed, by resolving the nearwall layer. A wide range of Reynolds numbers is investiga...

The effect of the spanwise discretisation on numerical calculations of the turbulent flow around a circular cylinder is systematically assessed at a subcritical Reynolds number of 10000 in the frame of three-dimensional large-eddy simulation. The eddy-viscosity k-equation subgrid scale model is implemented to evaluate unsteady turbulent flow field. Large-eddy simulation is known to be a reliabl...

Recently Shukurov et al [Phys Rev E 72, 025302 (2008)], made use of nonorthogonal curvilinear coordinate system on a dynamo Moebius strip flow, to investigate the effect of stretching by a turbulent liquid sodium flow. In plasma physics, Chui and Moffatt [Proc Roy Soc A 451,609,(1995)] (CM), considered non-orthogonal coordinates to investigate knotted magnetic flux tube Riemann metric. Here it ...

abstract weirs are the most common structures for discharge measurement in engineering research. streamline curvature, non hydrostatic pressure distribution on weir and nappe adherence to the weir lead to differences between calculated and measured discharges. thus discharge coefficient, which is the ratio of real and theoretic discharges, is usually less than unity. in circular weirs the press...

We consider the application of a new analytic method based on homotopy analysis to the solution of the steady flow of a viscous incompressible fluid past a fixed circular cylinder. The solutions obtained using this method produce some interesting results. For instance, an analytic verification of the critical Reynolds number Rd for which a standing vortex first appears behind the cylinder is gi...