ISSN:0025-5793    

DOI:10.1112/S002557930001367X

出版商:London Mathematical Society    

年代:1993

数据来源: WILEY

摘要:

AbstractAn oncoming two‐dimensional laminar boundary layer that develops an unstable inflection point and becomes three‐dimensional is described by the Hall‐Smith (1991) vortex/wave interaction equations. These equations are now examined in the neighbourhood of the position where the critical surface starts to form. A consistent structure is established in which an inviscid core flow is matched to a viscous buffer‐layer solution where the appropriate jump condition on the transverse shear stress is satisfied. The final result is a bifurcation equation for the (constant) amplitude of the wave pressure. A representative classical velocity profile is considered to illustrate solutions of this equation for a range of values of the wave‐numbers.

ISSN:0025-5793    

DOI:10.1112/S0025579300013693

出版商:London Mathematical Society    

年代:1993

数据来源: WILEY

摘要:

AbstractIn a previous paper (Grimshaw, 1990a) we showed that the resonant, or critical, flow of a rotating fluid past an axisymmetric obstacle placed on the axis of a cylindrical tube is described by a forced Korteweg‐de Vries equation for the amplitude of the dominant resonant mode. Here we show that in the anomalous but important case when the oncoming flow is uniform with uniform angular velocity a different theory is required which leads to an evolution equation describing finite‐amplitude waves. Some numerical solutions of this equation are described.

ISSN:0025-5793    

DOI:10.1112/S002557930001370X

出版商:London Mathematical Society    

年代:1993

数据来源: WILEY

ISSN:0025-5793    

DOI:10.1112/S0025579300013711

出版商:London Mathematical Society    

年代:1993

数据来源: WILEY

ISSN:0025-5793    

DOI:10.1112/S0025579300013723

出版商:London Mathematical Society    

年代:1993

数据来源: WILEY

ISSN:0025-5793    

DOI:10.1112/S0025579300013735

出版商:London Mathematical Society    

年代:1993

数据来源: WILEY

ISSN:0025-5793    

DOI:10.1112/S0025579300013747

出版商:London Mathematical Society    

年代:1993

数据来源: WILEY

ISSN:0025-5793    

DOI:10.1112/S0025579300013759

出版商:London Mathematical Society    

年代:1993

数据来源: WILEY

摘要:

AbstractWe obtain explicit lower bounds on the lattice packing densities δLof superballsGof quite a general nature, and we conjecture that as the dimensionnapproaches infinity, the bounds are asymptotically exact. If the conjecture were true, it would follow that the maximum lattice‐packing density of theIσ‐ball|x1|σ+…+|xn|σ⩽1is 2−n(1+σ(1))for each σ in the interval 1 ≤ σ ≤ 2.

ISSN:0025-5793    

DOI:10.1112/S0025579300013760

出版商:London Mathematical Society    

年代:1993

数据来源: WILEY

摘要:

AbstractIn Euclideand‐spaceEdwe prove inequalities between the intrinsic volumes (i.e., normalized quermassintegrals) of convex bodies and the successive minima of arbitrary lattices. The inequalities are tight and they generalize earlier results of Hadwiger and Henk for the integer lattice ℤd.

ISSN:0025-5793    

DOI:10.1112/S0025579300013772

出版商:London Mathematical Society    

年代:1993

数据来源: WILEY