arXiv subjects

E. Renzi

Publications and source records attributed to E. Renzi.

3 recordsLinked to original sources

arXiv2024

Toward a realistic model of multilayered bacterial colonies

Bacteria are prolific at colonizing diverse surfaces under a widerange of environmental conditions, and exhibit fascinating examples of self-organization across scales. Though it has recently attracted considerable interest, the role of mechanical forces in the collective behavior of bacterial colonies is not yet fully understood. Here, we construct a model of growing rod-like bacteria, such as Escherichia coli based purely on mechanical forces. We perform overdamped molecular dynamics simulations of the colony starting from a few cells in contact with a surface. As the colony grows, microdomains of strongly aligned cells grow and proliferate. Our model captures both the initial growth of a bacterial colony and also shows characteristic signs of capturing the experimentally observed transition to multilayered colonies over longer timescales. We compare our results with experiments on E. coli cells and analyze the statistics of microdomains.

cond-mat.soft↗

arXiv2012

Hydrodynamics of the Oscillating Wave Surge Converter in the open ocean

A potential flow model is derived for a large flap-type oscillating wave energy converter in the open ocean. Application of the Green's integral theorem in the fluid domain yields a hypersingular integral equation for the jump in potential across the flap. Solution is found via a series expansion in terms of the Chebyshev polynomials of the second kind and even order. Several relationships are then derived between the hydrodynamic parameters of the system. Comparison is made between the behaviour of the converter in the open ocean and in a channel. The degree of accuracy of wave tank experiments aiming at reproducing the performance of the device in the open ocean is quantified. Parametric analysis of the system is then undertaken. It is shown that increasing the flap width has the beneficial effect of broadening the bandwidth of the capture factor curve. This phenomenon can be exploited in random seas to achieve high levels of efficiency.

physics.flu-dyn↗

arXiv2012

Resonant behaviour of an oscillating wave energy converter in a channel

A mathematical model is developed to study the behaviour of an oscillating wave energy converter in a channel. During recent laboratory tests in a wave tank, peaks in the hydrodynamic actions on the converter occurred at certain frequencies of the incident waves. This resonant mechanism is known to be generated by the transverse sloshing modes of the channel. Here the influence of the channel sloshing modes on the performance of the device is further investigated. Within the framework of a linear inviscid potential-flow theory, application of the Green theorem yields a hypersingular integral equation for the velocity potential in the fluid domain. The solution is found in terms of a fast-converging series of Chebyshev polynomials of the second kind. The physical behaviour of the system is then analysed, showing sensitivity of the resonant sloshing modes to the geometry of the device, that concurs in increasing the maximum efficiency. Analytical results are validated with available numerical and experimental data.

physics.flu-dyn↗