An angular spectrum representation is applied for a description of statistical properties of arbitrary beamlike fields propagating through atmospheric turbulence. The Rytov theory is used for the characterization of the perturbation of the field by the atmosphere. In particular, we derive expressions for the cross-spectral density of a coherent and a partially coherent beam of arbitrary type in...

It has been generally assumed, since the work of von Karman and Howarth in 1938, that free decay of fully-developed turbulence is self-similar. We present here a simple phenomenological model of the decay of 3D incompressible turbulence, which predicts breakdown of self-similarity for low-wavenumber spectral exponents n in the range nc < n < 4, where nc is some threshold wavenumber. Calculation...

A von Karman vortex street generated in the usual way was subjected to a deceleration, thereby changing the ratio of longitudinal to lateral spacing between the vortices. Distortion of the individual vortices followed which resulted in annihilation of concentrated vortex regions and creation of a stationary wake flow. This wake flow was itself dynamically unstable and developed into a new vorte...

In 1986, Yakhot and Orszag developed a dynamic renormalization group method to solve the turbulence problem. In this paper, a particular random force is added to the Navier-Stokes Equation, and then following the standard renormalization group procedure, renormalization group equations and fixed points can be obtained. Together with some perturbation methods, many important turbulent constants ...

An analysis of the mean velocity profile in the intermediate region of wall-bounded turbulence shows that the well-known von Karman-Prandtl logarithmic law of the wall must be jettisoned in favor of a power law. An analogous analysis of the local structure of turbulence shows that the Kolmogorov-Obukhov scaling of the second and third structure functions is exact in the limit of vanishing visco...

In recent years, many researchers have studied vibration suppression of fluttering plates using piezoelectric actuators. Lots of these researchers have focused on optimal placement of piezoelectric patches to obtain maximum controllability. Although mass and stiffness characteristics of bonded patches can alter aeroelastic behavior of fluttering plates, few of them considered the effect of the ...

Light scattered from biological tissues can exhibit an inverse power law spectral component. We develop a model based on the Born approximation and von Karman (self-affine) spatial correlation of submicron tissue refractive index to account for this. The model is applied to light scattering spectra obtained from excised esophagi of normal and carcinogen-treated rats. Power law exponents used to...

The windshield is one of the major components in a vehicle that determines the injury to a pedestrian’s head. Therefore, it is critical to study the damage to windshield glazing so as to promote the protection structure for pedestrians. In this paper, classical plate theory in combination with the Green strain and the von Karman assumption is used to develop constitutive relations to describe t...

A recent technique can fabricate SiGe thin film islands on a glass layer, which itself lies on a silicon wafer. The islands initially have an inplane compressive strain. Upon annealing, the glass flows, and the islands relax. The resulting strain-free islands are used as substrates to grow epitaxial optoelectronic devices. This paper models the annealing process. A small island relaxes by inpla...

A layer-wise third order shear and normal deformable plate/shell theory (TSNDT) incorporating a cohesive zone model (CZM) is used to study the initiation and growth of delamination in straight and curved laminated beams. Upon satisfaction of the delamination criteria at a point on the interface between two layers, displacements there of two abutting points on the interface between the two layer...