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Although the full form of the Rayleigh–Plesset (RP) equation more accurately depicts the bubble behavior in a cavitating flow than its reduced form, it finds much less application than the latter in the computational fluid dynamic (CFD) simulation due to its high stiffness. The traditional variable time-step scheme for the full form RP equation is difficult to be integrated with the CFD program since it requires a tiny time step at the singularity point for convergence and this step size may be incompatible with time marching of conservation equations. This paper presents two stable and efficient numerical solution schemes based on the finite difference method and Euler method so that the full-form RP equation can be better accepted by the CFD program. By employing a truncation bubble radius to approximate the minimum bubble size in the collapse stage, the proposed schemes solve for the bubble radius and wall velocity in an explicit way. The proposed solution schemes are more robust for a wide range of ambient pressure profiles than the traditional schemes and avoid excessive refinement on the time step at the singularity point. Since the proposed solution scheme can calculate the effects of the second-order term, liquid viscosity, and surface tension on the bubble evolution, it provides a more accurate estimation of the wall velocity for the vaporization or condensation rate, which is widely used in the cavitation model in the CFD simulation. The legitimacy of the solution schemes is manifested by the agreement between the results from these schemes and established ones from the literature. The proposed solution schemes are more robust in face of a wide range of ambient pressure profiles. 

The energy emanating from hydrodynamic cavitation can play a significant role in enhancing manufacturing processes that utilize fluid medium as a force transmitter, a lubricant, or as a carrier. The fluid flow characteristics in a vortex cavitation generator is studied to determine how bubbles could be transported to a target location prior to implosion. Preliminary CFD simulations and experimental results have shown that the cavitating fluid stream exhibits a swirl flow pattern causing the cavitating stream to remain at the core of the stream. This phenomenon opens avenues for developing mechanisms for controlling and transporting cavitating bubbles to target locations prior to implosion. 

The Forward Search Experiment (FASER) at CERN’s Large Hadron Collider (LHC) has recently directly detected the first collider neutrinos. Neutrinos play an important role in all FASER analyses, either as signal or background, and it is therefore essential to understand the neutrino event rates. In this study, we update previous simulations and present prescriptions for theoretical predictions of neutrino fluxes and cross sections, together with their associated uncertainties. With these results, we discuss the potential for possible measurements that could be carried out in the coming years with the FASER neutrino data to be collected in LHC Run 3 and Run 4. 

The Forward Search Experiment (FASER) at CERN’s Large Hadron Collider (LHC) has recently directly detected the first collider neutrinos. Neutrinos play an important role in all FASER analyses, either as signal or background, and it is therefore essential to understand the neutrino event rates. In this study, we update previous simulations and present prescriptions for theoretical predictions of neutrino fluxes and cross sections, together with their associated uncertainties. With these results, we discuss the potential for possible measurements that could be carried out in the coming years with the FASER neutrino data to be collected in LHC Run 3 and Run 4.

Published by the American Physical Society2024 

The first results of the study of high-energy electron neutrino (𝜈𝑒) and muon neutrino (𝜈𝜇) charged-current interactions in the FASER⁢𝜈 emulsion-tungsten detector of the FASER experiment at the LHC are presented. A 128.8 kg subset of the FASER⁢𝜈 volume was analyzed after exposure to 9.5  fb−1 of √𝑠=13.6  TeV 𝑝⁢𝑝 data. Four (eight) 𝜈𝑒 (𝜈𝜇) interaction candidate events are observed with a statistical significance of 5.2⁢𝜎 (5.7⁢𝜎). This is the first direct observation of 𝜈𝑒 interactions at a particle collider and includes the highest-energy 𝜈𝑒 and 𝜈𝜇 ever detected from an artificial source. The interaction cross section per nucleon 𝜎/𝐸𝜈 is measured over an energy range of 560–1740 GeV (520–1760 GeV) for 𝜈𝑒 (𝜈𝜇) to be (1.2+0.8 −0.7)×10−38  cm2 GeV−1 [(0.5±0.2)×10−38  cm2 GeV−1], consistent with standard model predictions. These are the first measurements of neutrino interaction cross sections in those energy ranges. 

The first results of the study of high-energy electron neutrino (${\nu }_e$) and muon neutrino (${\nu }_{\mu }$) charged-current interactions in the$\mathrm{FASER}\nu$emulsion-tungsten detector of the FASER experiment at the LHC are presented. A 128.8 kg subset of the$\mathrm{FASER}\nu$volume was analyzed after exposure to$9.5{\mathrm{fb}}^{-1}$of$\sqrt{s}=13.6\mathrm{TeV}$$pp$data. Four (eight)${\nu }_e$(${\nu }_{\mu }$) interaction candidate events are observed with a statistical significance of$5.2\sigma$($5.7\sigma$). This is the first direct observation of${\nu }_e$interactions at a particle collider and includes the highest-energy${\nu }_e$and${\nu }_{\mu }$ever detected from an artificial source. The interaction cross section per nucleon$\sigma /E_{\nu }$is measured over an energy range of 560–1740 GeV (520–1760 GeV) for${\nu }_e$(${\nu }_{\mu }$) to be$({1.2}_{-0.7}^{+0.8})\times {10}^{-38}{\mathrm{cm}}^2{\mathrm{GeV}}^{-1}$[$(0.5\pm 0.2)\times {10}^{-38}{\mathrm{cm}}^2{\mathrm{GeV}}^{-1}$], consistent with standard model predictions. These are the first measurements of neutrino interaction cross sections in those energy ranges.

Published by the American Physical Society2024 

FASER, the ForwArd Search ExpeRiment, is an experiment dedicated to searching for light, extremely weakly-interacting particles at CERN's Large Hadron Collider (LHC). Such particles may be produced in the very forward direction of the LHC's high-energy collisions and then decay to visible particles inside the FASER detector, which is placed 480 m downstream of the ATLAS interaction point, aligned with the beam collisions axis. FASER also includes a sub-detector, FASERν, designed to detect neutrinos produced in the LHC collisions and to study their properties. In this paper, each component of the FASER detector is described in detail, as well as the installation of the experiment system and its commissioning using cosmic-rays collected in September 2021 and during the LHC pilot beam test carried out in October 2021. FASER has successfully started taking LHC collision data in 2022, and will run throughout LHC Run 3.