Two examples of explosive events observed with SUMER in transition region spectral lines are reported here; one detected in C iv 1548 Å, in a region within the northern polar coronal hole, and the other in O vi 1032 Å, in an active region. The event measured in C iv lasted ∼ 3 min and extended approximately a region of 8 arc sec along the slit (N-S) and 8 arc sec in the E-W direction. Velocitie...

The article deals with pneumatic and hot wire anemometry measurement on subsonic axi-symmetric air ejector. Performances of the ejector with and without pulsations of primary flow are compared, measuring of characteristic pressures and mass flow rates are performed and ejector efficiency is evaluated. The pulsations of primary flow are produced by a synthetic jet generator, which is placed in t...

Transition prediction of boundary layers has always been an important problem in fluid mechanics both theoretically and practically, yet notwithstanding the great effort made by many investigators, there is no satisfactory answer to this problem. The most popular method available is so-called e-N method which is heavily dependent on experiments and experience. The author has proposed improvemen...