arXiv subjects

Italo Bove

Publications and source records attributed to Italo Bove.

5 recordsLinked to original sources

arXiv2023

Which is greater: $\boldsymbol{e^π}$ or $\boldsymbol{π^{e}}$? An unorthodox solution to a classic puzzle

The question of the title is a famous puzzle in the field of recreational mathematics, and can be addressed by several approaches. A compilation of solutions, some of them very ingenious, can be found in [1]. In this contribution we present an alternative solution based on the second law of thermodynamics. The method can be extended to derive a more general result involving the exponential function.

physics.class-ph↗

arXiv2013

Polytropic process and tropical Cyclones

We show a parallelism between the expansion and compression of the atmosphere in the secondary cycle of a tropical cyclone with the fast expansion and compression of wet air in a bottle. We present a simple model in order to understand how the system (cyclone) draws energy from the air humidity. In particular we suggest that the upward (downward) expansion (compression) of the warm (cold) moist (dry) air follows a polytropic process, $PV^β$= constant. We show both experimentally and analytically that $β$ depends on the initial vapor pressure in the air. We propose that the adiabatic stages in the Carnot-cycle model for the tropical cyclone be replaced by two polytropic stages. These polytropic processes can explain how the wind wins energy and how the rain and the dry bands are produced inside the storm.

physics.ao-ph↗

arXiv2012

Air expansion in the water rocket

We study the thermodynamics of the water rocket in the thrust phase, taking into account the expansion of the air with water vapor, vapor condensation and the energy taken from the environment. We set up a simple experimental device with a stationary bottle and verified that the gas expansion in the bottle is well approximated by a polytropic process $PV^β$= constant, where the parameter $β$ depends on the initial conditions. We find an analytical expression for $β$ that only depends on the thermodynamic initial conditions and is in good agreement with the experimental results.

physics.flu-dyn↗

arXiv2008

Influence of coaxial cylinders on vortex breakdown in a closed flow

The effect of fixed cylindrical rods located at the centerline axis on vortex breakdown (VB) is studied experimentally and numerically. We find that the VB is enhanced for very small values of the rod radius $d$, while it is suppressed for values of $d$ beyond a critical value. In order to characterize this effect, the critical Reynolds number for the appearance of vortex breakdown as a function of the radius of the fixed rods and the different aspect ratios was accurately determined, using digital particle image velocimetry. The numerical and experimental results are compared showing an excellent agreement. In addition, a simple model in order to show that this effect also appears in open pipe flows is presented in the appendix.

physics.flu-dyn↗

arXiv2006

A simple mechanism for controlling vortex breakdown in a closed flow

This work is focused to study the development and control of the laminar vortex breakdown of a flow enclosed in a cylinder. We show that vortex breakdown can be controlled by the introduction of a small fixed rod in the axis of the cylinder. Our method to control the onset of vortex breakdown is simpler than those previously proposed, since it does not require any auxiliary device system. The effect of the fixed rods may be understood using a simple model based on the failure of the quasi-cylindrical approximation. We report experimental results of the critical Reynolds number for the appearance of vortex breakdown for different radius of the fixed rods and different aspect ratios of the system. Good agreement is found between the theoretical and experimental results.

physics.flu-dyn↗