Eli Leinov

Experimental and numerical investigation of the Richtmyer–Meshkov instability under re-shock conditions

(Received 6 October 2008 and in revised form 26 December 2008) An experimental and numerical systematic study of the growth of the Richtmyer– Meshkov instability-induced mixing following a re-shock is made, where the initial shock moves from the light fluid to the heavy one, over an incident Mach number range of 1.15–1.45. The evolution of the mixing zone following the re-shock is found to be independent of its amplitude at the time of the re-shock and to depend directly on the strength of the re-shock. A linear growth of the mixing zone with time following the passage of the re-shock and before the arrival of the reflected rarefaction wave is found. Moreover, when the mixing zone width is plotted as a function of the distance travelled, the growth slope is found to be independent of the re-shock strength. A comparison of the experimental results with direct numerical simulation calculations reveals that the linear growth rate of the mixing zone is the result of a bubble competition process.

Self-potential anomalies induced by water injection into hydrocarbon reservoirs

Our results imply that measurements of the spontaneous potential at a production well will combine contributions from both streaming and electrochemical effects, and may be used to detect an advancing waterfront some time before water breakthrough occurs at the well. Moreover, inversion of the measured signals could be used to determine the water saturation in the vicinity of the well, and to regulate flow into the well using control valves in order to maintain or increase oil production.

Reshocked Richtmyer-Meshkov instability: Numerical study and modeling of random multi-mode experiments

The evolution of the three-dimensional planar Richtmyer-Meshkov (RM) instability during a two shock wave interaction (i.e., reshock) is investigated by means of comparing numerical simulations and analytical modelling with experimental results of low Mach numbers (M < 1.5) and fairly high Atwood numbers (A ∼ 0.7). The study discusses and analyses the differences in the evolution of the mixing zone for two different types of initial perturbations, namely, multi-mode random initial perturbation with a narrow or wide bubble size distribution. More specifically, the study is focused on the agreement between numerical simulations and experiments performed with an unknown random initial perturbation. Using a large set of experimental results with different reshock arrival times and Mach numbers, the numerical simulations results are compared to the experimental results for a variety of different scenarios. This methodology allows a constrained comparison, while requiring good agreement for all cases. A comprehe...

Investigation of the Richtmyer–Meshkov instability under re-shock conditions

A systematic study has been made of the growth of the turbulent mixing zone (TMZ) after a re-shock in the framework of the Richtmyer–Meshkov instability where the initial shock is from the light fluid to the heavy one. The growth rate of the TMZ after the re-shock was found to be independent of its amplitude during the re-shock and to depend directly on the strength of the re-shock.

Investigation of guided waves propagation in pipe buried in sand

The inspection of pipelines by guided wave testing is a well-established method for the detection of corrosion defects in pipelines, and is currently used routinely in a variety of industries, e.g. petrochemical and energy. When the method is applied to pipes buried in soil, test ranges tend to be significantly compromised because of attenuation of the waves caused by energy radiating into the soil. Moreover, the variability of soil conditions dictates different attenuation characteristics, which in-turn results in different, unpredictable, test ranges. We investigate experimentally the propagation and attenuation characteristics of guided waves in pipes buried in fine sand using a well characterized full scale experimental apparatus. The apparatus consists of an 8 inch-diameter, 5.6-meters long steel pipe embedded over 3 meters of its length in a rectangular container filled with fine sand, and an air-bladder for the application of overburden pressure. Longitudinal and torsional guided waves are excited ...

Guided wave attenuation in pipes buried in sand

Long-range ultrasonic guided wave testing of pipelines is used routinely for detection of corrosion defects in a variety of industries, e.g. petrochemical and energy. When the method is applied to pipelines that are buried in soil, test ranges tend to be significantly compromised compared to those achieved for pipelines above ground because of the attenuation of the guided wave, due to energy leaking into the embedding soil. The attenuation characteristics of guided wave propagation in a pipe buried in sand are investigated using a full scale experimental rig. The apparatus consists of an 8”-diameter, 6-meters long steel pipe embedded over 3 meters in a rectangular container filled with sand and fitted with an air-bladder for the application of overburden pressure. Measurements of the attenuation of the T(0,1) and L(0,2) guided wave modes over a range of sand conditions, including loose, compacted, water saturated and drained, are presented. Attenuation values are found to be in the range of 1–5.5 dB/m. T...