scholarly journals Efficient algorithms for transient analysis of stochastic fluid flow models

2005 ◽  
Vol 42 (02) ◽  
pp. 531-549 ◽  
Author(s):  
Soohan Ahn ◽  
V. Ramaswami
Keyword(s):  
Fluid Flow ◽  
Transient Analysis ◽  
Busy Period ◽  
Flow Model ◽  
Flow Models ◽  
Period Distribution ◽  
The Matrix ◽  
Stochastic Fluid Flow ◽  
Stochastic Fluid ◽  
Transient And Steady State

We derive several algorithms for the busy period distribution of the canonical Markovian fluid flow model. One of them is similar to the Latouche-Ramaswami algorithm for quasi-birth-death models and is shown to be quadratically convergent. These algorithms significantly increase the efficiency of the matrix-geometric procedures developed earlier by the authors for the transient and steady-state analyses of fluid flow models.

scholarly journals Efficient algorithms for transient analysis of stochastic fluid flow models

2005 ◽  
Vol 42 (2) ◽  
pp. 531-549 ◽  
Author(s):  
Soohan Ahn ◽  
V. Ramaswami
Keyword(s):  
Fluid Flow ◽  
Transient Analysis ◽  
Busy Period ◽  
Flow Model ◽  
Flow Models ◽  
Period Distribution ◽  
The Matrix ◽  
Stochastic Fluid Flow ◽  
Stochastic Fluid ◽  
Transient And Steady State

We derive several algorithms for the busy period distribution of the canonical Markovian fluid flow model. One of them is similar to the Latouche-Ramaswami algorithm for quasi-birth-death models and is shown to be quadratically convergent. These algorithms significantly increase the efficiency of the matrix-geometric procedures developed earlier by the authors for the transient and steady-state analyses of fluid flow models.

scholarly journals HITTING PROBABILITIES AND HITTING TIMES FOR STOCHASTIC FLUID FLOWS: THE BOUNDED MODEL

2008 ◽  
Vol 23 (1) ◽  
pp. 121-147 ◽  
Author(s):  
Nigel G. Bean ◽  
Małgorzata M. O'Reilly ◽  
Peter G. Taylor
Keyword(s):  
Fluid Flow ◽  
Performance Measures ◽  
Flow Model ◽  
Fluid Flows ◽  
Hitting Times ◽  
Fluid Level ◽  
Probability Models ◽  
Hitting Probabilities ◽  
Stochastic Fluid Flow ◽  
Stochastic Fluid

We consider a Markovian stochastic fluid flow model in which the fluid level has a lower bound zero and a positive upper bound. The behavior of the process at the boundaries is modeled by parameters that are different than those in the interior and allow for modeling a range of desired behaviors at the boundaries. We illustrate this with examples. We establish formulas for several time-dependent performance measures of significance to a number of applied probability models. These results are achieved with techniques applied within the fluid flow model directly. This leads to useful physical interpretations, which are presented.

Stochastic fluid flow models for determining optimal switching thresholds

2005 ◽  
Vol 59 (1) ◽  
pp. 19-46 ◽  
Author(s):  
V. Aggarwal ◽  
N. Gautam ◽  
S.R.T. Kumara ◽  
M. Greaves
Keyword(s):  
Fluid Flow ◽  
Optimal Switching ◽  
Flow Models ◽  
Stochastic Fluid Flow ◽  
Stochastic Fluid

Study of the Response of PW Traffic Flow Model to a Bottleneck on a Circular Road and its Suitability for Heterogeneous Traffic Conditions

2021 ◽  
Vol 9 (4) ◽  
pp. 460-463
Keyword(s):  
Fluid Flow ◽  
Traffic Flow ◽  
Flow Model ◽  
Equation Model ◽  
Heterogeneous Traffic ◽  
Flow Conditions ◽  
Flow Models ◽  
Traffic Conditions ◽  
Model Response ◽  
Traffic Flow Models

The traffic flow conditions in developing countries are predominantly heterogeneous. The early developed traffic flow models have been derived from fluid flow to capture the behavior of the traffic. The very first two-equation model derived from fluid flow is known as the Payne-Whitham or PW Model. Along with the traffic flow, this model also captures the traffic acceleration. However, the PW model adopts a constant driver behavior which cannot be ignored, especially in the situation of heterogeneous traffic.This research focuses on testing the PW model and its suitability for heterogeneous traffic conditions by observing the model response to a bottleneck on a circular road. The PW model is mathematically approximated using the Roe Decomposition and then the performance of the model is observed using simulations.

Transient Coupled Borehole/Formation Fluid-Flow Model for Interpretation of Oil/Water Production Logs

SPE Journal ◽  
2016 ◽  
Vol 22 (01) ◽  
pp. 389-406 ◽  
Author(s):  
Amir Frooqnia ◽  
Carlos Torres-Verdín ◽  
Kamy Sepehrnoori ◽  
Rohollah Abdhollah-Pour
Keyword(s):  
Fluid Flow ◽  
Flow Model ◽  
Volume Fraction ◽  
Fluid Phase ◽  
Coupling Method ◽  
Average Pressure ◽  
Petrophysical Properties ◽  
Two Phase ◽  
Flow Models ◽  
Oil Water

Summary Interpretation of two-phase production logs (PLs) traditionally constructs borehole fluid-flow models decoupled from the physics of reservoir rocks. However, quantifying formation dynamic petrophysical properties from PLs requires simultaneous modeling of both borehole and formation fluid-flow phenomena. This paper develops a novel transient borehole/formation fluid-flow model that allows quantification of the effect of formation petrophysical properties on measurements acquired with production-logging tools (PLTs). We invoke a 1D, isothermal, two-fluid formulation to simulate borehole fluid-phase velocity, pressure, volume fraction, and density in oil/water-flow systems. The developed borehole fluid-flow model implements oil-dominant and water-dominant bubbly flow regimes with the inversion point taking place approximately when the oil volume fraction is equal to 0.5. Droplet diameter is dynamically modified to simulate interfacial drag effects, and to effectively account for variations of slip velocity in the borehole. Subsequently, a new successive iterative method interfaces the borehole and formation fluid-flow models by introducing appropriate source terms into the borehole fluid-phase mass-conservation equations. The novel iterative coupling method integrated with the developed borehole fluid-flow model allows dynamic modification of reservoir boundary conditions to accurately simulate transient behavior of borehole crossflow taking place across differentially depleted rock formations. In the case of rapid variations of near-borehole properties, frequent borehole/formation communication inevitably increases the computational time required for fluid-flow simulation. Despite this limitation, in a two-layer reservoir model penetrated by a vertical borehole, the coupling method accurately quantifies a 14% increase of volume-averaged oil-phase relative permeability of the low-pressure layer caused by through-the-borehole cross-communication of differentially depleted layers. Sensitivity analyses indicate that the alteration of near-borehole petrophysical properties primarily depends on formation average pressure, fluid-phase density contrast, and borehole-deviation angle. A practical application of the new coupled fluid-flow model is numerical simulation of borehole production measurements to estimate formation average pressure from two-phase selective-inflow-performance (SIP) analysis. This study suggests that incorporating static (shut-in) PL passes into the SIP analysis could result in misleading estimation of formation average pressure.

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