Forced phase winding

The presence of westward winds at the solstices leads to selective absorption of westward waves in the stratosphere and propagation of eastward waves to the mesosphere, where they force eastward winds. Near the equinoxes, on the other hand, eastward winds can be generated in the stratosphere by dissipation of eastward waves, while westward waves propagate to the mesosphere and force a mesospheric westward phase. In this way the seasonal cycle determines the timing of the SAO wind regimes. 

Continuous positive torque can be applied to a superconducting rotor using a three-phase winding, as indicated in Fig. 5. In the position shown, phase A exerts a force normal to each flat surface on the rotor as indicated by the forces F. During the instant represented by this rotor position no current flows through phases B or C. Current pulses, following in sequence from A to B to C to A as indicated, maintain rotation. 

Fig. 10. 33 Summary damage diagrams for gas detonations in non-dimensional coordinates 1 - spherical detonation 2 - cylindrical detonation 3 - planar detonation wave 4 - compression phase wind force 5 - compression phase 6 - rarefaction phase for a spherical detonation...

In summary, water movements in lakes occur in response to various natural forces, particularly wind, that transfer energy to the water. Both steady winds and rhythmic internal wave motions (i.e., oscillations) produce water currents in the surface layer as well as within the deeper internal layers of the water column, when they exist. These motions and their attendant currents may be in phase or in opposition, creating a complex mosaic and ever changing pattern of current magnitudes and directions over the sediment-water interface. The ultimate fate of these movements is to degrade into arrhythmic turbulent motions, which disperse the water and the chemicals within the water body (Wetzel, 2001). 

In between the resonance horns are regions of the parameter plane for which the response is quasi-periodic. Note that it is even possible for the frequencies to have a simple ratio and yet for the system to lie outside the corresponding resonance horn if the amplitude is raised. Figure 13.15 shows two time series for forcing with oj/oj0 = 10/1. At low forcing amplitude, rr = 0.005, we have phase locking and a simple if rather crumpled limit cycle. With rf = 0.01, however, the response is quasi-periodic a few cycles are shown and demonstrate quite well how the trajectory begins to wind around the torus. 

The location of the mixing zone depends on the river water runoff, the pattern of the nearshore zone (deep, shallow, wide, narrow), the range and phase of tide, wind direction and force, and sea level fluctuations. Therefore, this zone undergoes both seasonal and short-term variations. 

It is generally immaterial which phase, solid or fluid, is assumed to be at rest, and it is the relative velocity between the two that is important. An exception to this is met in some situations when the fluid stream has been previously influenced by solid walls and is in turbulent flow. The scale and intensity of turbulence then may be important parameters in the process. In wind tunnels, for example, where the solid shape is at rest and the stream of air is in motion, turbulence may give different forces on the solid than if the solid were moving at the same relative velocity through a quiescent and turbulence-free mass of air. Objects in free fall through a continuous medium may move in spiral patterns or rotate about their axis or both again the forces acting on them are not the same as when they are held stationary and the fluid is passed over them. 

Many chemicals escape quite rapidly from the aqueous phase, with half-lives on the order of minutes to hours, whereas others may remain for such long periods that other chemical and physical mechanisms govern their ultimate fates. The factors that affect the rate of volatilization of a chemical from aqueous solution (or its uptake from the gas phase by water) are complex, including the concentration of the compound and its profile with depth, Henry s law constant and diffusion coefficient for the compound, mass transport coefficients for the chemical both in air and water, wind speed, turbulence of the water body, the presence of modifying substrates such as adsorbents in the solution, and the temperature of the water. Many of these data can be estimated by laboratory measurements (Thomas, 1990), but extrapolation to a natural situation is often less than fully successful. Equations for computing rate constants for volatilization have been developed by Liss and Slater (1974) and Mackay and Leinonen (1975), whereas the effects of natural and forced aeration on the volatilization of chemicals from ponds, lakes, and streams have been discussed by Thibodeaux (1979). 

The movement of a chemical substance within the vapor phase occurs by the combined driving forces of flow and diffusion. An illustration of these effects can be visualized by considering a smokestack plume in the absence of wind, the plume will rise vertically in a more or less uniform column until it reaches an elevation where density considerations result in its spreading out into a relatively broad and flat mantle. When wind is factored into the equation, the plume may move in a more nearly horizontal direction, more or less parallel to the surface of the ground, and at certain wind speeds the plume structure can break up into loops or bends due to turbulent aerodynamic effects such as eddy formation. In addition, small eddies can result in the breakdown of the coherent plume structure, with the formation of... 

A cage rotor is used on single-phase a.c. motors, the turning force being produced in the way described previously for three-phase induction motors and shown in Fig. 2.49. Because both windings carry currents which are out of phase with each other, the motor is known as a split-phase motor. The phase... 

The period of the SAO, on the other hand, is regulated by the seasonal cycle because of one crucial difference between the QBO and the SAO The westward wind phase of the SAO in the stratosphere (see Fig. 11) is produced, not by wave forcing, but by the advection of westward zonal-mean momentum by the mean meridional circulation. In the tropics, the term v Uy in Eq. (8) cannot be neglected with respect to the Coriolis force, which vanishes at the equator. As shown in Fig. 13, the meridional velocity v is relatively large near the stratopause and its direction is such as to produce negative (westward) zonal-mean zonal winds. 

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