Computational investigations have been performed into the behavior of an incompressible fluid flow in the vicinity of a plane symmetric channel contraction. Our aim is to determine the critical Reynolds number, above which the flow becomes asymmetric with respect to the channel geometry using the bifurcation diagram. Three channels, which are characterized by the contraction ratio, are studied ...

We investigate the linear stability of unstably strati ed Poiseuille ow between two horizontal parallel plates under non-Boussinesq conditions. It is shown, that Squire's transformation can be used to reduce the three-dimensional stability problem to an equivalent two-dimensional one. The eigenvalue problem, consisting of the generalized Orr-Sommerfeld equations, is solved numerically using an ...

Full simulations of homogeneous isotropic turbulence containing a homogeneous passive scalar were made at low Reynolds numbers and various Prandtl numbers. The results show that the spectral behavior of the two fields are quite similar; both fields decay as power-law functions of time. However. the decay exponent is quite dependent on both the Reynolds and Prandtl numbers. The decay exponent of...

An experimental investigation was carried out to study mixed convection heat transfer from Al2O3-water nanofluid inside a vertical, W-shaped, copper-tube with uniform wall temperature. The tests covered different ranges of some involved parameters including Reynolds number, temperature and particles volume fraction. The results showed that the rate of heat transfer coefficient improved with Rey...

The last lecture has been more words than equations. Today we are going to do some paradigmatic calculations. We’ll start with -one at high Reynolds number and one at low Reynolds number –which represent critical ideas for the subject of fluid mechanics. The first calculation is arguably the most important applied-mathematical idea of the twentieth century (at least I would argue it), and it is...

The stresslet provides a simple model of the flow created by a small, freely swimming and neutrally buoyant aquatic organism and shows that the far field fluid disturbance created by such an organism in general decays as one over distance squared. Here we discuss a quieter swimming mode that eliminates the stresslet component of the flow and leads to a faster spatial decay of the fluid disturba...

Despite high predation pressure, planktonic copepods remain one of the most abundant groups on the planet. Their escape response provides one of most effective mechanisms to maximize evolutionary fitness. Owing to their small size (100 µm) compared with their predators (>1 mm), increasing viscosity is believed to have detrimental effects on copepods' fitness at lower temperature. Using high-spe...

Burgers’ equation, involving very high Reynolds numbers, is numerically solved by using a new approach based on the distributed approximating functional for representing spatial derivatives of the velocity field. For moderately large Reynolds numbers, this simple approach can provide very high accuracy while using a small number of grid points. In the case where the Reynolds number >10, the exa...