scholarly journals Development of closure relations for the motion of Taylor bubbles in vertical and inclined annular pipes using high-fidelity numerical modeling

2020 ◽  
Vol 32 (6) ◽  
pp. 063306
Author(s):  
T. Mitchell ◽  
C. Leonardi
Keyword(s):  
Numerical Modeling ◽  
High Fidelity ◽  
Closure Relations ◽  
Annular Pipes ◽  
Taylor Bubbles

Doppler echo evaluation of pulmonary venous-left atrial pressure gradients: human and numerical model studies

2000 ◽  
Vol 279 (2) ◽  
pp. H594-H600 ◽  
Author(s):  
Michael S. Firstenberg ◽  
Neil L. Greenberg ◽  
Nicholas G. Smedira ◽  
David L. Prior ◽  
Gregory M. Scalia ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Left Atrial ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
High Fidelity ◽  
Pressure Gradients ◽  
Bernoulli Equation ◽  
Venous Flow ◽  
Model Studies ◽  
Pulmonary Venous Flow

The simplified Bernoulli equation relates fluid convective energy derived from flow velocities to a pressure gradient and is commonly used in clinical echocardiography to determine pressure differences across stenotic orifices. Its application to pulmonary venous flow has not been described in humans. Twelve patients undergoing cardiac surgery had simultaneous high-fidelity pulmonary venous and left atrial pressure measurements and pulmonary venous pulsed Doppler echocardiography performed. Convective gradients for the systolic (S), diastolic (D), and atrial reversal (AR) phases of pulmonary venous flow were determined using the simplified Bernoulli equation and correlated with measured actual pressure differences. A linear relationship was observed between the convective ( y) and actual ( x) pressure differences for the S ( y = 0.23 x + 0.0074, r = 0.82) and D ( y = 0.22 x + 0.092, r = 0.81) waves, but not for the AR wave ( y = 0.030 x + 0.13, r = 0.10). Numerical modeling resulted in similar slopes for the S ( y = 0.200 x − 0.127, r = 0.97), D ( y = 0.247 x − 0.354, r= 0.99), and AR ( y = 0.087 x − 0.083, r = 0.96) waves. Consistent with numerical modeling, the convective term strongly correlates with but significantly underestimates actual gradient because of large inertial forces.

High-Fidelity Numerical Modeling of Spark Plug Erosion

2019 ◽  
Author(s):  
Douglas Breden ◽  
Anand Karpatne ◽  
Kenta Suzuki ◽  
Laxminarayan Raja
Keyword(s):  
Numerical Modeling ◽  
High Fidelity ◽  
Spark Plug

scholarly journals Numerical modeling of oscillating Taylor bubbles

2016 ◽  
Vol 10 (1) ◽  
pp. 578-598 ◽  
Author(s):  
S. Ambrose ◽  
D. M. Hargreaves ◽  
I. S. Lowndes
Keyword(s):  
Numerical Modeling ◽  
Taylor Bubbles

Computational Fluid Dynamics (CFD) Simulations of Taylor Bubbles in Vertical and Inclined Pipes with Upward and Downward Liquid Flow

SPE Journal ◽  
2021 ◽  
pp. 1-16
Author(s):  
Enrique Lizarraga-Garcia ◽  
Jacopo Buongiorno ◽  
Eissa Al-Safran
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Distribution Parameter ◽  
Bubble Velocity ◽  
Wide Range ◽  
Computational Fluid Dynamics Cfd ◽  
Closure Relations ◽  
Slug Flows ◽  
Inclined Pipes ◽  
Taylor Bubbles

Summary Two-phase flow is a common occurrence in pipes of oil and gas developments. Current predictive tools are based on the mechanistic two-fluid model, which requires the use of closure relations to predict integral flow parameters such as liquid holdup (or void fraction) and pressure gradient. However, these closure relations carry the highest uncertainties in the model. In particular, significant discrepancies have been found between experimental data and closure relations for the Taylor bubble velocity in slug flow, which has been determined to strongly affect the mechanistic model predictions (Lizarraga-García 2016). In this work, we study the behavior of Taylor bubbles in vertical and inclined pipes with upward and downward flow using a validated 3D computational fluid dynamics (CFD) approach with level set method implemented in a commercial code. A total of 56 cases are simulated, covering a wide range of fluid properties, pipe diameters, and inclination angles: Eo ∈ [10, 700]; Mo ∈ [1×10–6, 5×103]; ReSL ∈ [–40, 10]; θ ∈ [5°, 90°]. For bubbles in vertical upward flows, the simulated distribution parameter, C0, is successfully compared with an existing model. However, the C0 values of downward and inclined slug flows where the bubble becomes asymmetric are shown to be significantly different from their respective vertical upward flow values, and no current model exists for the fluids simulated here. The main contributions of this work are (1) the relatively large 3D numerical database generated for this type of flow, (2) the study of the asymmetric nature of inclined and some vertical downward slug flows, and (3) the analysis of its impact on the distribution parameter, C0.

Numerical Modeling of Movements of Taylor Bubbles in Stagnant Liquid Hydrogen Fluids

2021 ◽  
Author(s):  
J.L. Zuo ◽  
K. Zhang ◽  
S. Wu ◽  
Z. Huang ◽  
N. Zhang ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Liquid Hydrogen ◽  
Taylor Bubbles

High-fidelity numerical modeling of the Upper Mississippi River under extreme flood condition

2016 ◽  
Vol 98 ◽  
pp. 97-113 ◽  
Author(s):  
Ali Khosronejad ◽  
Trung Le ◽  
Petra DeWall ◽  
Nicole Bartelt ◽  
Solomon Woldeamlak ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Mississippi River ◽  
High Fidelity ◽  
Upper Mississippi River ◽  
Extreme Flood ◽  
Flood Condition

Using the Theory of Planned Behavior to Predict Faking in Selection Exercises Varying in Fidelity

2018 ◽  
Vol 17 (3) ◽  
pp. 155-160 ◽  
Author(s):  
Daniel Dürr ◽  
Ute-Christine Klehe
Keyword(s):  
Theory Of Planned Behavior ◽  
Planned Behavior ◽  
Predictive Validity ◽  
Group Discussion ◽  
Role Play ◽  
Selection Procedure ◽  
High Fidelity ◽  
Selection Research ◽  
Play Group

Abstract. Faking has been a concern in selection research for many years. Many studies have examined faking in questionnaires while far less is known about faking in selection exercises with higher fidelity. This study applies the theory of planned behavior (TPB; Ajzen, 1991 ) to low- (interviews) and high-fidelity (role play, group discussion) exercises, testing whether the TPB predicts reported faking behavior. Data from a mock selection procedure suggests that candidates do report to fake in low- and high-fidelity exercises. Additionally, the TPB showed good predictive validity for faking in a low-fidelity exercise, yet not for faking in high-fidelity exercises.

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