Dr. Ayelet Goldstein

Published 

1. Goldstein A. and Eyal O. Local behavior near triple point in laminar two-phase flow in an arbitrary.  Applied Mathematical modelling, 2021 (accepted). 

2. Goldstein A., Eyal O., Ullmann A., Brauner Neima Wall and interfacial shear stresses in stratified laminar two-phase stratified flow in pipes. J. Multiphase Flow, 2021 (accepted). 

3. Eyal O. and Goldstein A. Gauss’ Law for Moving Charges from First Principles.  Results in Physics, Volume 14, 2019, 

4. Eyal O. and Goldstein A. Green’s Function Method for Solving the Separated Two-Phase Flow in Inclined Tubes with Driving Force Contributions. Journal of Multiphase Flow, Volume 117, 103-113, 2019. 

5. Eyal O. and Goldstein A. Potential problems on surfaces: with or without boundary, subjected to discrete distributed sources. Results in Physics, Volume 12, 1697-1711, 2019. 

6. Goldstein A. and Eyal O. Radiation Fields Created by accelerated Relativistic charges: A Simple approach Based on Inertial Moving Charges, Results in Physics, Volume 12, 1104-1110, 2019.

7. Goldstein, A. and O. Eyal, Relationships among charges, fields, and potential on spherical surfaces boundary value problems, Results in Physics, Volume 11, 335-349, 2018.

8. Goldstein, A., Ullmann, A., and Brauner, N., Exact solutions of core-annular laminar inclined flows, J. Multiphase Flow, Volume 93, 178-204, 2017.

9. Goldstein A., Brauner, N., Ullmann, A., Characteristics of Stratified Laminar Flows in Inclined Pipes, J. Multiphase Flow, Volume 75, 267-287, 2015.

10. Ullmann, A., Goldstein A., Brauner, N., Gas-Liquid and Liquid-Liquid Stratified Flows Analytical and Mechanistic Models The Szewalski Institute of Fluid-Flow Machinery, Polish Academy of sciences. Transactions of the Institute of Fluid-Flow Machinery 117, 59-79, 2005.

11. Ullmann, M Zamir, Goldstein and N. Brauner, Closure Relations for the Shear Stresses in Two-Fluid Models for Laminar Stratified Flow, Int. J. Multiphase Flow, 30(7-8) 877-900, 2004,

Published

11. 1. Goldstein, A. and Ofer Eyal, Superposition of Driving Force Densities contributions as a method for solving two-phase flow in inclined tubes; bulk, interface and triple-points behavior, of the 12th International Conference on Computational Heat, Mass and Momentum Transfer (ICCHMT2019), Roma Tre University and Sapienza University of Rome, Italy, September 2019.
    2. Goldstein, A. and Ofer Eyal, Potential Problems on Surfaces: with or without Boundary, Subjected to Discrete Distributed Sources, of the 12th International Conference on Computational Heat, Mass and Momentum Transfer (ICCHMT2019), Roma Tre University and Sapienza University of Rome, Italy, September 2019.
    3. Goldstein, A., Ullmann, A., Brauner, N., Characteristics of Separated Laminar Flows in Inclined Pipes, Proc. of the 7^th International Conference on Multiphase Flow ICMF, Tampa FL USA, May 30 June 4, 2010.
    4. Goldstein, A., Ullmann, A., Brauner, N., Laminar Two Phase Separated Flows: Analytical Solutions, Proc. of the 13^th International Heat Transfer Conf., paper No. MTH10, Sydney Australia, 13-18 August, 2006.
    5. Goldstein, A., Ullmann, A., Brauner, N., Gas-Liquid and Liquid-Liquid Stratified Flows: Analytical and Mechanistic Models of the 4^th Int. conf. on Transport Phenomena and Multiphase Systems (Ed. J. Mikielewicz , D. Butrymowicz, M. Trela and T. Cieslinski), HEAT2005, Gdansk, Poland, June 26-30, 2005.
    6. Goldstein, A. and Ofer Eyal, Green’s Function Method for Solving the Separated Two-Phase Flow in Inclined Tubes by Superposition, Proc. of the 35^th Israeli Conference on Mechanical Engineering ICME2018, Ben-Gurion University of the Negev, October 2018.
    7. Goldstein, A. and Ofer Eyal, An Analytical Solution for Creeping Flow in a Narrow Gap between Two Surfaces Created by Injected Flux, Proc. of the 35^th Israeli Conference on Mechanical Engineering ICME2018, Ben-Gurion University of the Negev, October 2018.
    8. Goldstein, A., Ullmann, A., Brauner, N., Benefits of Adding a Lubricating Phase for Transportation of a Viscous Fluid in Inclined CAF’s, Proc. of the 34^th Israeli Conference on Mechanical Engineering ICME2016, Technion, Israel, November 22-23, 2016.
    9. Goldstein, A., Ullmann, A., Brauner, N., Exact Solutions of Core-Annular Laminar Inclined Flows, Proc. of the 34^th Israeli Conference on Mechanical Engineering ICME2016, Technion, Israel, November 22-23, 2016.
    10. Goldstein, A., Ullmann, A., Brauner, N., Adding a Lubricating Phase for Conveying of a Viscous Liquid in Inclined CAF’s, The 6^th International Conference on Energy Challenges and Mechanics ECM6, Inverness, Scotland, UK, August 14-18, 2016.
    11. Goldstein, A., Ullmann, A., Brauner, N., Wall and Interfacial Shear Stresses in Separated Laminar Flows, Proc. of the 5^th European-Japanese Two-Phase Flow Group Meeting, Spoleto, Italy, 20-25 September 2009.
    12. Goldstein, A., Ullmann, A., Brauner, N., Characteristics of Laminar Separated Flows in Inclined Pipes, The 47^th European Two-Phase Flow Group Meeting, Bled Slovenia, Multi-Phase Flow, June 2009.
    13. Goldstein, A., Ullmann, A., Brauner, N., Laminar Two-Phase Separated Flows: Analytical and Mechanistic Models of the 30^th Israeli Conference on Mechanical Engineering, Multi-Phase Flow, Tel-Aviv University, Tel-Aviv, Israel, May 2005.

Guideline of the scientific work
Exact solutions for separated two-phase flow are useful as benchmark for numerical codes and for testing closure relations for simplified 1D Two-Fluid (TF) models. Recently we obtained a complete set of exact solutions for laminar flows in inclined pipes. These include all possible configurations of stratified flows (STF) with concave and convex interfaces, and core-annular flows (CAF) with various core eccentricities. The exact solutions are used to analyze the local and averaged wall and interfacial shear stresses for these various flow geometries. A closed-form analytical expression for the average interfacial shear stress was obtained for all cases of STF. The limiting behavior of the local shear stresses at the triple-point, where the interface meets the pipe wall, is determined by residue calculus. It is shown that the shear stresses profiles at the vicinity of the triple points are determined by the fluids viscosity ratio and the contact angle. The usefulness of the exact solutions for testing closure for approximate TF models is discussed. The future plane is to improve the prediction of stability boundaries of various separated flow configurations in the pipe geometry via two fluid models

Articles to be Submitte

1. Eyal O. and Goldstein A. Magnetic dipoles as tools for deriving some of the laws of electrodynamics: an intuitive approach . Results in Physics, Volume XX (to be appeared).
2. Goldstein A. and Eyal O. Modes of movement of a rigid body. Applied Mechanical modelling.