Stagnation frequency

Let CO be the angular velocity of rotation this is equal to Inf where/is the disk frequency or number of revolutions per second. The distance r of any point from the center of the disk is identical with the distance from the flow stagnation point. The hnear velocity of any point on the electrode is cor. We see when substituting these quantities into Eq. (4.34) that the effects of the changes in distance and hnear vefocity mutuaUy cancel, so that the resulting diffusion-layer thickness is independent of distance. 

Marchildon et al (M3) related oscillation of a falling cylinder to movement of the front stagnation point, and obtained an expression for the frequency ... 

In hydrodynamic cavitation, the tensile stress is of relatively long duration and plenty of caviration nuclei are usually available. As a result, cavitation occurs when the total net pressure, or the stagnation pressure, becomes approximately equal to the vapor pressure of the liquid. In acoustic cavitation, the cyclic pressure required to produce cavitation is a function of the frequency, the partial pressure of any dissolved gas, and the population of cavitation nuclei. For frequencies above about 200.(XX) Hz. the threshold pressure for cavitation increases with the square of the frequency and is almust independent of the degree of gas saturation. For frequencies below 200,000 Hz. the threshold pressure is a funelion of the partial pressure of the dissolved gas. In saturated liquids at sound pressures less than a... 

Raman spectroscopy provided most of the early experimental data on molecular vibrational frequencies, but with the advent of commercial infrared spectrometers in the 1940 s, the technique stagnated with respect to infrared spectroscopy. This was despite the fact that Raman spectroscopy enjoyed, and still enjoys, certain natural advantages over infrared spectroscopy, viz. 

The images of the single-brush flame were complemented by profiles of temperature, velocity, and calculated strain rates at the stagnation plane (not shown here), and the effects of forcing amplitude and frequency on the reduction in the mean extinction strain rate close to the axis were quantified while previous results [15] were extended to include the effects of bulk velocity and separation on extinction times. The amplitude of imposed oscillations was quoted in terms of the rms of the axial velocity fluctuations at the nominal stagnation point normalized by the bulk velocity [14],... 

Figure 5.3 Free jet center line beam velocity (u/uj, temperature T/TJ, gas density (n/nj, and hard sphere collision frequency (v/vj as a function of the distance from the nozzle, in units of nozzle diameters for the case of 7 = 5/3. Note that none of these parameters depends upon the stagnation pressure. Taken with permission from D.R. Miller (1988).

Let us show how one can And the limiting trajectory and collision frequency of particles with the cylinder without solving these equations. The limiting trajectory (see Fig. 10.9) ends at the back point Op =n, y = y. To determine y, one should proceed as follows. When the particle is moving along the critical trajectory near the back stagnation point, the velocity is Ur = = 0 and since the particle mo-... 

Typically, pulse combustors operate at frequencies from 20 to 250 Hz. Pressure oscillation in the combustion chamber of 10 kPa produces velocity oscillation in the tailpipe of about 100 m/s, so the instantaneous velocity of a gas jet at the tailpipe exit varies from 0 to 100 m/s (Keller et al., 1992). Although pulse combustors deliver flue gases at a higher pressure than the inlet air pressure, the resulting increase in stagnation pressure is relatively small. This restricts practical applications of pulse combustors to the systems where pressure drop is not critical. The amplitude of the pressure rise may vary from 10% (domestic heating applications) to 100% as for heavy-duty pulse combustors for industrial use (Kentfleld, 1993). The output power for commercially available pulse combustors ranges from 70 to 1000 kW. 

AC Electro-Osmotic Flow, Fig. 7 (a) Collection of E. coli bacteria in tap water along the stagnation lines of ACEO flow on An microelectrodes at low frequency (100 Hz) and moderate voltage (1 V). (b) Preferential... 

Figure 4 A 172 MHz broad-band scan (lower trace) and high-resolution spectrum (upper trace) of phenol and water in helium at a stagnation pressure of 100 kPa. Three lines can be recognized in the low-resolution spectrum a doublet consisting of a strong and a weak component of the 6oe

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