scholarly journals Influence of the history force on inertial particle advection: Gravitational effects and horizontal diffusion

2013 ◽  
Vol 88 (4) ◽  
Author(s):  
Ksenia Guseva ◽  
Ulrike Feudel ◽  
Tamás Tél
Keyword(s):  
Inertial Particle ◽  
Gravitational Effects ◽  
Horizontal Diffusion ◽  
History Force ◽  
Particle Advection

Artificial satellite orbit computations

1966 ◽  
Vol 25 ◽  
pp. 363-371
Author(s):  
P. Sconzo
Keyword(s):  
Artificial Satellite ◽  
Satellite Orbit ◽  
Artificial Satellites ◽  
Orbital Elements ◽  
Differential Correction ◽  
Gravitational Effects ◽  
Short Intervals ◽  
The Subject ◽  
Introductory Discussion ◽  
Orbit Computation

In this paper an orbit computation program for artificial satellites is presented. This program is operational and it has already been used to compute the orbits of several satellites.After an introductory discussion on the subject of artificial satellite orbit computations, the features of this program are thoroughly explained. In order to achieve the representation of the orbital elements over short intervals of time a drag-free perturbation theory coupled with a differential correction procedure is used, while the long range behavior is obtained empirically. The empirical treatment of the non-gravitational effects upon the satellite motion seems to be very satisfactory. Numerical analysis procedures supporting this treatment and experience gained in using our program are also objects of discussion.

scholarly journals Effects of Parameterized Diffusion on Simulated Hurricanes

2012 ◽  
Vol 69 (7) ◽  
pp. 2284-2299 ◽  
Author(s):  
Richard Rotunno ◽  
George H. Bryan
Keyword(s):  
Boundary Layer ◽  
Numerical Simulations ◽  
Dominant Role ◽  
Control Factor ◽  
Vertical Diffusion ◽  
Maximum Wind ◽  
Gradient Wind ◽  
Horizontal Diffusion ◽  
Budget Analysis ◽  
Parameterized Model

Abstract In this study the authors analyze and interpret the effects of parameterized diffusion on the nearly steady axisymmetric numerical simulations of hurricanes presented in a recent study. In that study it was concluded that horizontal diffusion was the most important control factor for the maximum simulated hurricane intensity. Through budget analysis it is shown here that horizontal diffusion is a major contributor to the angular momentum budget in the boundary layer of the numerically simulated storms. Moreover, a new scale analysis recognizing the anisotropic nature of the parameterized model diffusion shows why the horizontal diffusion plays such a dominant role. A simple analytical model is developed that captures the essence of the effect. The role of vertical diffusion in the boundary layer in the aforementioned numerical simulations is more closely examined here. It is shown that the boundary layer in these simulations is consistent with known analytical solutions in that boundary layer depth increases and the amount of “overshoot” (maximum wind in excess of the gradient wind) decreases with increasing vertical diffusion. However, the maximum wind itself depends mainly on horizontal diffusion and is relatively insensitive to vertical diffusion; the overshoot variation with vertical viscosity mainly comes from changes in the gradient wind with vertical viscosity. The present considerations of parameterized diffusion allow a new contribution to the dialog in the literature on the meaning and interpretation of the Emanuel potential intensity theory.

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