排序方式： 共有34条查询结果，搜索用时 31 毫秒
21.
M.J. Manton 《地球物理与天体物理流体动力学》2013,107(2):83-99
There is some experimental evidence by Schotland (1957) and by Telford and Cottis (1964) that there is an interaction region associated with the wake of a small droplet such that other droplets inside this region eventually collide with that droplet. It is shown that the existence of such a region produces a significant collision rate between droplets of comparable size in a vertical shear flow. The general features of the collision process are in agreement with the experimental results of Jonas and Goldsmith (1972). 相似文献
22.
23.
24.
M. J. Manton 《Pure and Applied Geophysics》1978,116(6):1030-1048
An approximate infra-red radiation scheme, employing essentially the cooling to space approximation, is included in a one-dimensional model of the atmospheric boundary layer. The approximate scheme is found not to produce significant errors in the behaviour of the dynamical model when integrated over a few hours. Radiative cooling is shown to be important in the development of a clear well-mixed layer which is capped by an essentially dry region; in particular, convetive instability is induced and this enhances the rate of entrainment of dry air. The development of fog is found to require sound models of both radiative transfer and turbulent diffusion. 相似文献
25.
M. J. Manton 《Pure and Applied Geophysics》1977,115(3):547-559
Summary The motion of an aerosol can be described by a general force balance equation, independent of the detailed structure of the flow, provided that the interaction between the external flow field and the local flow induced by the aerosol is weak. A necessary and sufficient condition for the interaction to be weak is that the length scale of the aerosol is much less than that of the external flow. High and low Reynolds number regimes can be distinguished for the motion of an aerosol relative to the external flow. In some extreme conditions the equation of motion reduces to an algebraic equation for the aerosol velocity.After submission of this article the author was made aware of a similar treatment published inTopics of Appl. Phys., 12 (Turbulence, Chapter 7), Springer Verlag, Berlin, which at the time of the article's submission had not yet appeared in Australia. (Ed.) 相似文献
26.
The structure of free convection in an atmospheric surface layer is modelled as a field of plumes rising from the ground. The plumes occupy nearly one-half of the total fluid volume and they coalesce slowly as they rise. The model behaviour is consistent with the results obtained commonly by dimensional analysis under the assumption that the friction velocity is an irrelevant parameter in an unstable constant-flux layer. 相似文献
27.
M. J. Manton 《Boundary-Layer Meteorology》1980,19(3):337-358
A boundary-layer model, which incorporates an eddy diffusivity for turbulent transports, is presented. It is shown that this model can predict the appropriate behaviour for mixed layers produced by surface shear, free convection and mechanical mixing. The model is used to consider the development of cumulus clouds, which are shown generally to be convectively unstable at cloud top. Thus the entrainment of dry air leads to a very low cloud-water content in cumulus cloud. 相似文献
28.
M. J. Manton 《Boundary-Layer Meteorology》1971,1(3):264-276
The Miles theory of sea wave growth implies that, in a coordinate system moving with the wave phase velocity, closed streamline cats'-eyes are formed around the critical height where the mean wind speed equals the wave phase speed. From inspection of the equations of motion (the Rayleigh system), it is shown that these cats'-eyes may lie either over the wave crests or over the wave troughs, depending upon the behaviour of the mean wind profile. The validity of using Miles first approximation of the streamfunction' to approximate the actual streamline pattern is also discussed. 相似文献
29.
M. J. Manton 《Boundary-Layer Meteorology》1971,2(2):152-160
The sea state and the air flow above the sea during active wave generation is discussed. From energy balance considerations, a relationship between the wind duration and the phase speed of the waves at the peak of the energy spectrum is derived and compared with previous experimental results. It is shown that fluid viscosity plays a negligible role in the transfer of momentum from the air to the sea. Consequently the drag coefficient for the air-sea interface is related only to the apparent roughness of the sea surface. 相似文献
30.
Five nodules of eclogite, one nodule of garnet peridotite and one sample of kimberlite from the Roberts Victor mine were analyzed for concentrations of U, Th, Pb, Rb and Sr and isotopic compositions of Pb and Sr. In the eclogites, U content ranges from 0.09 to 0.26 ppm, Th from 0.35 to 1.1 ppm, Pb from 0.79 to 5.5 ppm, Rb from 2.1 to 28 ppm and Sr from 133 to 346 ppm;206Pb/204Pb ratios range from 14.8 to 18.5,207Pb/204Pb from 14.9 to 15.7,208Pb/204Pb from 35.2 to 38.5. The garnet peridotite contains 0.22 ppm U, 0.97 ppm Th, 1.05 ppm Pb, 6.9 ppm Rb and 108 ppm Sr and the kimberlite contains 2.5 ppm U, 30 ppm Th, 37 ppm Pb, 113 ppm Rb and 2040 ppm Sr. The lead in the eclogites has two components, a lead pyroextractable at 1100–1200° and a non-pyroextractable residual lead. In three of the eclogites, which are to some extent altered, a proportion of the pyroextractable lead may be contaminating lead from the kimberlite, but an altered kyanite eclogite does not appear to be contaminated by this same kimberlite. The pyroextractable lead from a less altered eclogite contains a much larger proportion of206Pb. Compositions calculated for the residual leads vary greatly. In many of the pyroextraction runs the primary eclogitic phases disappeared and the new phases plagioclase, clinopyroxene and a magnetic iron compound were formed. Why part of the lead should have been retained by these new phases is not understood. 相似文献