Segment Description of Turbulence

2DV Nonlinear k-ε Turbulence Modeling of Stratified Flows

The commonly used linear k-ε turbulence model is shown to be incapable of accurate prediction of turbulent flows, where non-isotropy is dominant. Two examples of non-isotropic flows, which have a wide range of applications in marine waters, are saline water flow and the stratified flows due to temperature gradients. These relate to stratification and consequently, variation of density through...

A Markov chain approximation of a segment description of chaos

We test a Markov chain approximation to the segment description (Li, 2007) of chaos (and turbulence) on a tent map, the Minea system, the Hénon map, and the Lorenz system. For the tent map, we compute the probability transition matrix of the Markov chain on the segments for segment time length (iterations) T = 1, 2, 3, 100. The matrix has 1, 2, 4 tents corresponding to T = 1, 2, 3; and is almos...

Segmentation Independent Estimates of Turbulence Parameters

We present a new approach for analyzing local power law processes and apply it to temperature measurements from the upper atmosphere. We segment the data and use the wavelet scale spectrum to estimate the parameters of the power law, the scale factor and the exponent. These parameters vary from segment to segment. Part of this variation is due to the non-stationarity of the data. Another part i...

A Phase Diversity Experiment to Measure Piston Misalignment on the Segmented Primary Mirror of the Keck II Telescope

We are developing a technique to measure segment misalignment of large telescopes based on wavefront estimation using phase-diverse (inand out-of-focus) images. We report the current results of an experiment to measure piston errors on the Keck II primary segmented mirror, through atmospheric turbulence, using phase-diverse phase retrieval. The segment piston errorss are separated from the rand...

Development of one-point statistical closure from a spectral description of the turbulence