arXiv subjects
Publications and source records attributed to Maciej Lisicki.
We present four different ways of deriving the Oseen tensor which is the fundamental solution to the Stokes equations for an incompressible viscous fluid. This solution corresponds to a point force acting on an infinite fluid. The derivations follow the books of Kim & Karilla, Zapryanov & Tabakova, Dhont, and Pozrikidis.
A simple method for presenting a dynamic transition between Fresnel and Fraunhofer diffraction zones is considered. Experiments are conducted on different apertures and diffraction patterns are photographed at various distances between the screen and the aperture. A diverging lens is introduced into the experimental setup to provide enlarged Fresnel diffraction patterns. Fresnel and Fraunhofer diffraction patterns and dynamic transition between them can be easily obtained on a distance of few meters, what gives an opportunity to use our setup as a lecture experiment. Photographs of transition for square aperture are shown and discussed.