Power and cross— spectra for the turbulent atmospheric motion and transports in the domain of wave number frequency space: Theoretical aspects

1994 ◽  
Vol 11 (4) ◽  
pp. 491-498 ◽  
Author(s):  
M. Y. Totagi
Keyword(s):  
Wave Number ◽  
Frequency Space ◽  
Number Frequency ◽  
Atmospheric Motion

Turbulence functions useful for probes (space–time correlation) and for scattering (wave-number–frequency spectrum) analysis

1968 ◽  
Vol 46 (23) ◽  
pp. 2683-2702 ◽  
Author(s):  
I. P. Shkarofsky
Keyword(s):  
Characteristic Size ◽  
Time Correlation ◽  
Exponential Model ◽  
Time Correlation Function ◽  
Maximum Energy ◽  
Confluent Hypergeometric Function ◽  
Space Time ◽  
Wave Number ◽  
Taylor’S Hypothesis ◽  
Number Frequency

The wave-number–frequency dependent spectral function, S(k, ω), and the space–time correlation function, C(r, t), are considered in a turbulent flowing plasma. The decay mechanisms are associated with either velocity fluctuations about the mean convection velocity or diffusion effects or attachment, or combinations of these, including the Brownian motion model. The ψ(k, ω) function, which is the ratio of S(k, ω) to its frequency-integrated value, depends on the mechanism and exhibits a profile which can be Gaussian, Lorentzian, a Z function, a Hermite polynomial modification of the Gaussian, or a confluent hypergeometric function. Anisotropic forms are also considered.The function C(r, t), obtained by convolving ψ (r, t) with C(r), the space autocorrelation function, is next considered. Adopting a Gaussian or an exponential model (which may be anisotropic) for C(r), we illustrate C(r, t) forms, which can readily be manipulated. Furthermore, letting r = 0, we derive two conditions for the applicability of Taylor's hypothesis. The assumption of frozen flow is not necessary, only that the root-mean-square Lagrangian displacement in a given time, associated with the decay, be much smaller than both the flow distance and the characteristic size of blobs having maximum energy.

Space-time-wave number-frequency Z(x,t,k,f) analysis of SAW generation on fluid filled cylindrical shells

Ultrasonics ◽  
2004 ◽  
Vol 42 (1-9) ◽  
pp. 383-389 ◽  
Author(s):  
Loı̈c Martinez ◽  
Bruno Morvan ◽  
Jean Louis Izbicki
Keyword(s):  
Cylindrical Shells ◽  
Space Time ◽  
Wave Number ◽  
Number Frequency

Determination of the Reflectivity of Wind Waves with the Wave Number Frequency Spectrum

1978 ◽  
Vol 21 (1) ◽  
pp. 21-50
Author(s):  
Akira Ishida ◽  
Yasuomi Okamoto ◽  
Masakatsu Furuta
Keyword(s):  
Frequency Spectrum ◽  
Wind Waves ◽  
Wave Number ◽  
Number Frequency
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