David Schmoranzer

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Flow due to a commercially available vibrating quartz fork is studied in gaseous helium, He I and He II, over a wide range of temperatures and pressures. On increasing the driving force applied to the fork, the drag changes in character from laminar (characterized by a linear drive vs velocity dependence) to turbulent (characterized by a quadratic drive vs(More)
Introduction The standard Baker pH technique is used to visualize flows due to an oscillating cylinder of square crosssection in water at room temperature. Transition to turbulence is clearly indicated by the appearance of large flow structures mostly in the form of columnar vortices. The measurements are analyzed in terms of the critical Keulegan-Carpenter(More)
In this report we give a concise overview of the results on the transition to turbulence in normal and superfluid 4 He obtained in the laboratory of superfluidity in Prague using a quartz tuning fork oscillating at 32 kHz as a detector. The capabilities of the tuning fork as a flow detector were explored both in self-induced and externally generated flows,(More)
We report on an experimental study of the behavior of a number of commercially available quartz tuning forks oscillating in a classical cryogenic fluid, in the form of either liquid helium I or gaseous helium, extending our previous studies [M. Blazkova Phys. Rev. E 75, 025302 (2007)]. Measurements of the damping of the oscillations allowed us to deduce the(More)
When a hot body A is thermally connected to a cold body B, the textbook knowledge is that heat flows from A to B. Here, we describe the opposite case in which heat flows from a colder but constantly heated body B to a hotter but constantly cooled body A through a two-phase liquid-vapor system. Specifically, we provide experimental evidence that heat flows(More)
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