A new instability mechanism is described in accretion flows where the gas is accelerated from a stationary shock to a sonic surface. The instability is based on a cycle of acoustic and entropic waves in this subsonic region of the flow. When advected adiabatically inward, entropy perturbations trigger acoustic waves propagating outward. If a shock is present at the outer boundary, acoustic wave...

This paper deals with the output tracking problem of a MIMO system subjected to a class of actuator faults and unmatched perturbations. The proposed methodology is based on high order sliding mode observation and identification techniques. A dynamic sliding surface is proposed using a backstepping-like design strategy in order to counteract the effects of the unmatched perturbations. Whereas a ...

Abstract. We study the influence of an aperiodic extended surface perturbation on the surface critical behaviour of the two-dimensional Ising model in the extreme anisotropic limit. The perturbation decays as a power κ of the distance l from the free surface with an oscillating amplitude Al=(−1)l where fl =0, 1 follows some aperiodic sequence with an asymptotic density equal to 1/2 so that the ...

We study the surface diffusion flow acting on a class of general (non–axisymmetric) perturbations of cylinders Cr in IR3. Using tools from parabolic theory on uniformly regular manifolds, and maximal regularity, we establish existence and uniqueness of solutions to surface diffusion flow starting from (spatially–unbounded) surfaces defined over Cr via scalar height functions which are uniformly...

We consider the Euler equations describing nonlinear waves on the free surface of a twodimensional inviscid, irrotational fluid layer of finite depth. For large surface tension, Bond number larger than 1=3, and Froude number close to 1, the system possesses a one-parameter family of small-amplitude, traveling solitary wave solutions. We show that these solitary waves are spectrally stable with ...

In this study, the influence of aerosols, surface roughness length, soil moisture, and synergistic interactions among these factors on tropical convective rainfall focused along a sea breeze front are explored within idealized cloud-resolving modeling simulations using the Regional Atmospheric Modeling System (RAMS). The idealized RAMS domain setup is representative of the coastal Cameroon rain...

Skin blood flow responses in the human forearm, assessed by three commonly used technologies-single-point laser-Doppler flowmetry, integrated laser-Doppler flowmetry, and laser-Doppler imaging-were compared in eight subjects during normothermic baseline, acute skin-surface cooling, and whole body heat stress (Δ internal temperature=1.0±0.2 degrees C; P<0.001). In addition, while normothermic an...

We study the spectral (in)stability of one-dimensional solitary and cnoidal waves of various Boussinesq systems. These systems model three-dimensional water waves (i.e., the surface is two-dimensional) with or without surface tension. We present the results of numerous computations examining the spectra related to the linear stability problem for both stationary solitary and cnoidal waves with ...