ASSOCIATE PROFESSOR URI SHAVIT
Personal Background
Academic Degrees
1987 BSc (cum laude) Agricultural Engineering, Technion – IIT
1990 MSc (cum laude) Agricultural Engineering, Technion – IIT
1994 PhD Mechanical Engineering, Carnegie Mellon University (CMU), Pittsburgh, PA, USA
Academic Appointments
2008 - present Associate Professor, Faculty of Civil and Environmental
Engineering, Technion – IIT
Research Interest
Environmental fluid mechanics and transport in porous media.
Prof. Shavit and his research group study transport phenomena in complex environments such as stream beds, canopy flows, and coral reefs. The laboratory, field, and theoretical studies include mean flow models, solute dispersion, particles re-suspension, volume averaging theories, applications of PIV and PLIF, groundwater-stream interaction, N-cycle and other biogeochemical processes in streambeds and soils.
Significant Projects
1998 – 2006: Coordination of a regional Jordanian, Palestinian, and Israeli research group in collaboration for mutual hydrological research projects, a total budget of about $1,000,000 funded by the U.S. Agency for International Development, MERC.
List of Recent Publications
1. Shavit, U., Rosenzweig, R., and Assouline, S., Free Flow at the Interface of Porous Surfaces: Generalization of the Taylor Brush Configuration. Transport in Porous Media, (54), 345–360, 2004.
2. Farber, E., Vengosh, A., Gavrieli, I., Marie, A., Bullen, T.D., Mayer, B., Holtzman, R., Segal, M., and Shavit U., Hydrochemistry and Isotope Geochemistry of the Lower Jordan River: Constraints for the Origin and Mechanisms of Salinization. Geochimica et Cosmochimica Acta, 68(9), 1989–2006, 2004.
3. Lahav O, Lu Y, Shavit U, and Loewenthal RE. Modeling H2S(g) emission rates in gravity sewage collection systems. Journal of Environmental Engineering- ASCE 130 (11): 1382-1389, 2004.
4. Segal-Rozenhaimer, M., Shavit, U., Holtzman, R., Vengosh, A., Farber, E., Gavrieli, I., Bullen, T., Mayer, B., and Shaviv, A., Nitrogen Pollutants, Sources and Processes along the Lower Jordan River. Journal of Environmental Quality, 33, 1440-1451, 2004.
5. Assouline S. and Shavit U. Effects of Management Policies, Including Artificial Recharge, on the Salinization Process in a Coastal Aquifer. Water Resources Research, 40 (4): Art. No. W04101 April 2004.
6. Holtzman, R., Shavit, U., Segal-Rozenhaimer, M., Gavrieli, I., Marei, A., Farber, E., and Vengosh, A. Quantifying Ground Water Inputs along the Lower Jordan River. Journal of Environmental Quality, 34(3): 897-906, 2005.
7. Master, Y., Shavit, U., and Shaviv, A., Modified Isotope Pairing Technique to Study N Transformations in Polluted Aquatic Systems: Theory, Environmental Science & Technology, 39 (6): 1749-1756, 2005.
8. Kremen, A., Bear, J., Shavit, U., and Shaviv, A., A model demonstrating the potential for coupled nitrification denitrification in soil aggregates, Environmental Science & Technology, 39 (11): 4180-4188, 2005.
9. Farber, E., Vengosh, A., Gavrieli, I., Marie, A., Bullen, T.D., Mayer, B., Holtzman, R., Segal, M., and Shavit, U., Management scenarios for the Jordan River salinity crisis, Applied Geochemistry, 20 (11): 2138-2153 2005.
10. Shavit, U., Lowe, R.J., and Steinbuck J.V., Intensity Capping: a simple method to improve cross-correlation PIV results, Experiments in Fluids 42(2): 225-240, 2007.
11. Farber, E., Vengosh, A., Gavrieli, I., Marie, A., Bullen, T.D., Mayer, B., Polak, A., and Shavit, U. The geochemistry of groundwater resources in the Jordan Valley: impact of the Rift Valley brines. Applied Geochemistry 22 (3): 494-514, 2007.
12. Rosenzweig, R., and U. Shavit, The laminar flow field at the interface of a Sierpinski carpet configuration, Water Resources Research, 43, W10402, 2007.
14. Duman, T. and Shavit, U., An apparent interface location as a tool to solve the porous interface flow problem, Transport in Porous Media, under revision, accepted with minor revision.
Chapters in Books
1. Shavit, U., R. Holtzman, M. Segal, A. Vengosh, E. Farber, I. Gavrieli, T. Bullen, and ECO- Research Team, Water Sources and Quality Along the Lower Jordan River, Regional Study. in Water Resources Quality, Preserving the Quality of our Water Resources, Edited by H. Rubin, H.P. Nachtnebel, J. Furst, and U. Shamir, Springer-Verlag, Berlin, pp. 127-148, 2002.
2. Shavit, U., R. Holtzman, M. Segal, I. Gavrieli, E. Farber, and A. Vengosh, The Lower Jordan River, International Seminar on Nuclear War and Planetary Emergencies, The Science and Culture Series, New Jersey, Word Scientific, 2004.
3. Ravid Rosenzweig and Uri Shavit, Theoretical and Numerical Study of Flow at the Interface of Porous Media, in Dynamics of Fluids and Transport through Fractured Rock, Edited by Boris Faybishenko, AGUs Geophysical Monograph series, American Geophysical Union, Washington, D.C, 2005.
4. Shavit, U., Rosenzweig, R., and Assouline, S., Free Flow at the Interface of Porous Surfaces: Generalization of the Taylor Brush Configuration. Transport in Porous Media, (54), 345–360, 2004.
5. Farber, E., Vengosh, A., Gavrieli, I., Marie, A., Bullen, T.D., Mayer, B., Holtzman, R., Segal, M., and Shavit U., Hydrochemistry and Isotope Geochemistry of the Lower Jordan River: Constraints for the Origin and Mechanisms of Salinization. Geochimica et Cosmochimica Acta, 68(9), 1989–2006, 2004.
6. Lahav O, Lu Y, Shavit U, and Loewenthal RE. Modeling H2S(g) emission rates in gravity sewage collection systems. Journal of Environmental Engineering- ASCE 130 (11): 1382-1389, 2004.
7. Segal-Rozenhaimer, M., Shavit, U., Holtzman, R., Vengosh, A., Farber, E., Gavrieli, I., Bullen, T., Mayer, B., and Shaviv, A., Nitrogen Pollutants, Sources and Processes along the Lower Jordan River. Journal of Environmental Quality, 33, 1440-1451, 2004.
8. Assouline S. and Shavit U. Effects of Management Policies, Including Artificial Recharge, on the Salinization Process in a Coastal Aquifer. Water Resources Research, 40 (4): Art. No. W04101 April 2004.
9. Holtzman, R., Shavit, U., Segal-Rozenhaimer, M., Gavrieli, I., Marei, A., Farber, E., and Vengosh, A. Quantifying Ground Water Inputs along the Lower Jordan River. Journal of Environmental Quality, 34(3): 897-906, 2005.
11. Kremen, A., Bear, J., Shavit, U., and Shaviv, A., A model demonstrating the potential for coupled nitrification denitrification in soil aggregates, Environmental Science & Technology, 39 (11): 4180-4188, 2005.
12. Farber, E., Vengosh, A., Gavrieli, I., Marie, A., Bullen, T.D., Mayer, B., Holtzman, R., Segal, M., and Shavit, U., Management scenarios for the Jordan River salinity crisis, Applied Geochemistry, 20 (11): 2138-2153 2005.
13. Shavit, U., Lowe, R.J., and Steinbuck J.V., Intensity Capping: a simple method to improve cross-correlation PIV results, Experiments in Fluids 42(2): 225-240, 2007.
14. Farber, E., Vengosh, A., Gavrieli, I., Marie, A., Bullen, T.D., Mayer, B., Polak, A., and Shavit, U. The geochemistry of groundwater resources in the Jordan Valley: impact of the Rift Valley brines. Applied Geochemistry 22 (3): 494-514, 2007.
15. Rosenzweig, R., and U. Shavit, The laminar flow field at the interface of a Sierpinski carpet configuration, Water Resources Research, 43, W10402, 2007.
16. Lowe. R.J., Shavit, U., Falter, J.L., Koseff, J.R., and Monismith, S.G., Canopy and porous media modeling of momentum balance in coral pavements under oscillatory and unidirectional flows, Limnology and Oceanography, in press.
Abstracts
Intensity Capping: a simple method to improve cross-correlation PIV results
Shavit, U., Lowe, R.J. and Steinbuck J.V.
Experiments in Fluids 42(2): 225-240, 2007
A common source of error in Particle Image Velocimetry (PIV) is the presence of bright spots within the images. These bright spots are characterized by grayscale intensities much greater than the mean intensity of the image and are typically generated by intense scattering from seed particles. The displacement of bright spots can dominate the cross-correlation calculation within an interrogation window, and may thereby bias the resulting velocity vector. An efficient and easy-to-implement image-enhancement procedure is described to improve PIV results when bright spots are present. The procedure, called Intensity Capping, imposes a user-specified upper limit to the grayscale intensity of the images. The displacement calculation then better represents the displacement of all particles in an interrogation window and the bias due to bright spots is reduced. Four PIV codes and a large set of experimental and simulated images were used to evaluate the performance of Intensity Capping. The results indicate that Intensity Capping can significantly increase the number of valid vectors from experimental image pairs and reduce displacement error in the analysis of simulated images. A comparison with other PIV image-enhancement techniques shows that Intensity Capping offers competitive performance, low computational cost, ease of implementation, and minimal modification to the images.
The geochemistry of groundwater resources in the Jordan Valley: impact of the Rift Valley brines
Farber, E., Vengosh, A., Gavrieli, I., Marie, A., Bullen, T.D., Mayer, B., Polak, A. and Shavit, U.
Applied Geochemistry 22 (3): 494-514, 2007
The laminar flow field at the interface of a Sierpinski carpet configuration
Rosenzweig, R. and U. Shavit
Water Resources Research 43, W10402, 2007
The problem of laminar flow in a combined free and saturated porous domain was investigated using a Sierpinski carpet configuration. The three dimensional steady state micro-scale velocities were measured using a Particle Image Velocimeter (PIV) and computed numerically. The macro-scale velocity profiles were then obtained by averaging the micro-macro-scale velocities. A comparison between the measured and computed velocities showed a good fit. The macro-scale velocity profile was calculated using the Modified Brinkman Equation (MBE), which was recently derived for two-dimensional brush configurations. The MBE was developed for unidirectional, laminar flows, assuming that the porous medium planar porosity follows a step function. A new analytical solution of the MBE, was developed and applied using no calibration or curve fitting. It was shown that although the MBE was originally derived for a unidirectional microscopic flow field, the macroscopic representation of the complex microscopic flow in the Sierpinski configuration can be well described by the solutions of the MBE.
Canopy and porous media modeling of momentum balance in coral pavements under oscillatory and unidirectional flows
Lowe. R.J., Shavit, U., Falter, J.L., Koseff, J.R., and Monismith, S.G.,
Limnology and Oceanography, in press.
Both canopy flow and porous media theories have been developed independent of one another to predict flow through submerged porous structures. These approaches are very similar, albeit with some key differences in how canopy resistance forces are parameterized. Canopy models provide a means of parameterizing the shear stresses that occur at the top of the canopy whereas porous media models often offer a simpler and more tractable way of parameterizing turbulent form drag based on simple morphological metrics and empirical relationships already in the hydrology literature. We developed a set of equations combining aspects of both models and applied this hybridized model to predict the flow structure within an experimental canopy formed by the branching coral Porites compressa, using model parameter values obtained from the literature. Results from the model predictions agreed well with direct measurements of flow speed and flow forces derived from Particle Image Velocimetry (PIV) under conditions of both unidirectional and wave-driven oscillatory flow.
An apparent interface location as a tool to solve the porous interface flow problem
Duman, T. and Shavit, U.
Transport in Porous Media, under revision, accepted with minor revision
