Browsing Mathematics by Author "Zhang, Keke"
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Asymptotic and numerical solutions of the initial value problem in rotating planetary fluid cores
Liao, X.; Zhang, Keke (Oxford University Press / Royal Astronomical Society, 2010)An initial state of fluid motion in planetary cores or atmospheres, excited, for example, by the giant impact of an asteroid or an earthquake and then damped by viscous dissipation, decays towards the state of rigidbody ... 
Asymptotic theory of resonant flow in a spheroidal cavity driven by latitudinal libration
Zhang, Keke; Chan, K.H.; Liao, X. (Cambridge University Press, 2012) 
Countertraveling waves in rotating RayleighBénard convection.
Li, Ligang; Liao, X.; Zhang, Keke (American Physical Society, 2008)Linear and nonlinear countertraveling waves in a fluidfilled annular cylinder with realistic noslip boundary conditions uniformly heated from below and rotating about a vertical axis are investigated. When the gap of ... 
An exact solution for arbitrarily rotating gaseous polytropes with index unity
Kong, Dali; Zhang, Keke; Schubert, Gerald (Oxford University Press for Royal Astronomical Society, 2015)Many gaseous planets and stars are rapidly rotating and can be approximately described by a polytropic equation of state with index unity.We present the first exact analytic solution, under the assumption of the oblate ... 
Hydrothermal convection in moderately thin spherical shells.
Dai, Zifeng; Zhang, Keke; Liao, X.; Schubert, Gerald (American Physical Society, 2008)Hydrothermal convection of pore water with a temperaturedependent viscosity within a permeable, internally heated, moderately thin spherical shell is investigated by both a perturbation analysis and a direct numerical ... 
Linear and nonlinear instabilities in rotating cylindrical RayleighBénard convection
Li, Ligang; Liao, X.; Chan, K.H.; Zhang, Keke (American Physical Society, 2008)Linear and nonlinear convection in a rotating annular cylinder, under experimental boundary conditions, heated from below and rotating about a vertical axis are investigated. In addition to the usual physical parameters ... 
Nonlinear dynamo action in rotating convection and shear
Zhang, Pu; Gilbert, Andrew D.; Zhang, Keke (Cambridge University Press, 2005)Magnetic field amplification by the motion of an electrically conducting fluid is studied, using a rotating planelayer geometry. The fluid flow is driven by convection, and by a moving bottom boundary, which leads to an ... 
On fluid flows in precessing narrow annular channels: asymptotic analysis and numerical simulation
Zhang, Keke; Kong, Dali; Liao, X. (Cambridge University Press, 2010)We consider a viscous, incompressible fluid confined in a narrow annular channel rotating rapidly about its axis of symmetry with angular velocity Ω that itself precesses slowly about an axis fixed in an inertial frame. ... 
On fluid flows in precessing spheres in the mantle frame of reference
Zhang, Keke; Chan, K.H.; Liao, X. (American Institute of Physics, 2010)We investigate, through both asymptotic and numerical analysis, precessionally driven flows of a homogeneous fluid confined in a spherical container that rotates rapidly with angular velocity Ω and precesses slowly with ... 
On fluid motion in librating ellipsoids with moderate equatorial eccentricity
Zhang, Keke; Chan, K.H.; Liao, X. (Cambridge University Press, 2011) 
On the initialvalue problem in a rotating circular cylinder
Zhang, Keke; Liao, X. (Cambridge University Press, 2008)The initialvalue problem in rapidly rotating circular cylinders is revisited. Four different but related analyses are carried out: (i) we derive a modified asymptotic expression for the viscous decay factors valid for the ... 
The onset of convection in rotating circular cylinders with experimental boundary conditions
Zhang, Keke; Liao, X. (Cambridge University Press, 2009)Convective instabilities in a fluidfilled circular cylinder heated from below and rotating about its vertical axis are investigated both analytically and numerically under experimental boundary conditions. It is found ... 
Precessing cylinders at the second and third resonance: Turbulence controlled by geostrophic flow
Jiang, Jianfei; Kong, Dali; Zhu, Rixiang; Zhang, Keke (American Physical Society, 20150908)We investigate, via both asymptotic analysis and direct numerical simulation, precessionally driven flow of a homogeneous fluid confined in fluidfilled circular cylinders that rotate rapidly about their symmetry axis and ... 
Simulations of nonlinear porewater convection in spherical shells
Dai, Zifeng; Zhang, Keke; Schubert, Gerald; Liao, X. (American Institute of Physics, 2008)Hydrothermal convection of pore water of uniform viscosity within a permeable, internally heated spherical shell bounded by two concentric spherical surfaces of inner radius ri and outer radius ro is investigated by fully ... 
Swimming motion of rodshaped magnetotactic bacteria: the effects of shape and growing magnetic moment.
Kong, Dali; Lin, Wei; Pan, Yongxin; Zhang, Keke (Frontiers, 2014)We investigate the swimming motion of rodshaped magnetotactic bacteria affiliated with the Nitrospirae phylum in a viscous liquid under the influence of an externally imposed, timedependent magnetic field. By assuming ... 
Thermalgravitational wind equation for the windinduced gravitational signature of giant gaseous planets: mathematical derivation, numerical method, and illustrative solutions
Schubert, G; Zhang, Keke; Kong, Dali; Schubert, Gerald (American Astronomical Society, 20150620)The standard thermal wind equation (TWE) relating the vertical shear of a flow to the horizontal density gradient in an atmosphere has been used to calculate the external gravitational signature produced by zonal winds in ... 
A threedimensional multilayered spherical dynamic interface dynamo using the MalkusProctor formulation
Chan, K.H.; Liao, X.; Zhang, Keke (IOP Publishing / American Astronomical Society, 2008)We investigate a fully threedimensional and multilayered spherical dynamic interface dynamo using a finiteelement method based on the threedimensional tetrahedralization of the whole spherical system. The dynamic interface ... 
Windinduced odd gravitational harmonics of Jupiter
Kong, Dali; Zhang, Keke; Schubert, Gerald (Oxford University Press for Royal Astronomical Society, 2015)While the rotational distortion of Jupiter makes a major contribution to its lowermost order even zonal gravitational coefficients Jn with n ≥ 2, the component of the zonal winds with equatorial antisymmetry, if sufficiently ...