Nonstationary Processes

The two-phase model of vapor-gas-liquid medium in axisymmetric two-dimensional formulation, taking into account vaporization is constructed. The nonstationary processes of boiling vapor-water mixture outflow from high-pressure vessels as a result of depressurization are studied. The problems of shock waves action on filled by gas-liquid mixture volumes are solved.

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Investigation of two-dimensional nonstationary processes of outflow a gas-saturated liquid from axisymmetric vessels

Proceedings of the Mavlyutov Institute of Mechanics ◽

10.21662/uim2012.1.008 ◽

2012 ◽

Vol 9 (1) ◽

pp. 47-52

Author(s):

R.Kh. Bolotnova ◽

V.A. Buzina

Keyword(s):

Comparative Analysis ◽

Numerical Model ◽

Liquid Mixture ◽

Phase Model ◽

Test Problems ◽

Two Dimensional ◽

Nonstationary Processes ◽

Saturated Liquid ◽

Two Phase ◽

One Dimensional

The two-dimensional and two-phase model of the gas-liquid mixture is constructed. The validity of numerical model realization is justified by using a comparative analysis of test problems solution with one-dimensional calculations. The regularities of gas-saturated liquid outflow from axisymmetric vessels for different geometries are established.

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Estimation of Spatial Deformation for Nonstationary Processes via Variogram Alignment

Technometrics ◽

10.1080/00401706.2021.1883481 ◽

2021 ◽

pp. 1-14

Author(s):

Ghulam A. Qadir ◽

Ying Sun ◽

Sebastian Kurtek

Keyword(s):

Nonstationary Processes ◽

Spatial Deformation

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Mathematical modeling of nonstationary processes of heat and mass transfer in a rectangular cable channel

Russian Electrical Engineering ◽

10.3103/s1068371215110139 ◽

2015 ◽

Vol 86 (11) ◽

pp. 656-660 ◽

Cited By ~ 3

Author(s):

N. M. Trufanova ◽

E. Yu. Navalikhina ◽

T. V. Gataulin

Keyword(s):

Mathematical Modeling ◽

Mass Transfer ◽

Heat And Mass Transfer ◽

Nonstationary Processes ◽

Cable Channel

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Geophysical signal processing using sequential Bayesian techniques

Geophysics ◽

10.1190/geo2012-0180.1 ◽

2013 ◽

Vol 78 (3) ◽

pp. V87-V100 ◽

Cited By ~ 2

Author(s):

Caglar Yardim ◽

Peter Gerstoft ◽

Zoi-Heleni Michalopoulou

Keyword(s):

Posterior Probability ◽

Signal To Noise Ratio ◽

Multiple Model ◽

Nonstationary Processes ◽

Ensemble Kalman Filters ◽

Bayesian Techniques ◽

Strongly Nonlinear ◽

Posterior Probability Density ◽

Geophysical Signal ◽

Seismic Measurements

Sequential Bayesian techniques enable tracking of evolving geophysical parameters via sequential observations. They provide a formulation in which the geophysical parameters that characterize dynamic, nonstationary processes are continuously estimated as new data become available. This is done by using prediction from previous estimates of geophysical parameters, updates stemming from physical and statistical models that relate seismic measurements to the unknown geophysical parameters. In addition, these techniques provide the evolving uncertainty in the estimates in the form of posterior probability density functions. In addition to the particle filters (PFs), extended, unscented, and ensemble Kalman filters (EnKFs) were evaluated. The filters were compared via reflector and nonvolcanic tremor tracking examples. Because there are numerous geophysical problems in which the environmental model itself is not known or evolves with time, the concept of model selection and its filtering implementation were introduced. A multiple model PF was then used to track an unknown number of reflectors from seismic interferometry data. We found that when the equations that define the geophysical problem are strongly nonlinear, a PF was needed. The PF outperformed all Kalman filter variants, especially in low signal-to-noise ratio tremor cases. However, PFs are computationally expensive. The EnKF is most appropriate when the number of parameters is large. Because each technique is ideal under different conditions, they complement each other and provide a useful set of techniques for solving sequential geophysical inversion problems.

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