Study on the Suppression of Vortex Induced Oscillation of Cylinder by Forward Jets

Oscillation induced by vortex shedding often causes fatigue damage of slender cylindrical structures in many engineering fields, so it is significant to study the suppression of vortex induced oscillation. We focus on the methods of experimental test to study on the suppression effect of vortex induced oscillation of cylinder with single freedom at Reynolds number of 2.4 × 104. We designed a set of device with forward water jet to suppress vortex induced oscillation. We found the most notable observation from a serials of experiments: reduction of displacement of cylinder exhibits two distinct modes separated by a sudden and very pronounced decrease in the extent of cross-flow displacement at a critical value of the geometric and flow variables followed by what appears to be a saturation regime where no further decrease is observed. These results will provide some meaningful and evaluable references for practical application in ocean engineering.

Forward jets and large rapidity gaps

Hadronic jets are extremely abundant at the LHC, and testing QCD in various corners of phase-space is important to understand backgrounds and some specific signatures of new physics. In this article, various measurements aiming at probing QCD in configurations where the theory modelling becomes challenging are presented. Azimuthal angle de-correlations are sensitive to hard as well as soft QCD emission, and in most of the events jets are produced in a back-to-back configuration. Events where jets have a large rapidity separation are also rare, and those without additional radiation between the jets are exponentially suppressed. The modelling of radiation between very forward and backward jets is complicated, and may require theoretical tools different with respect to those normally used for central, high-[Formula: see text] events. Observables can be constructed that are sensitive to all these effects, such as the study of azimuthal angle de-correlations in events where the two leading jets have large rapidity separations. The two general-purpose detectors of the LHC have measured these observables, and for some of them interesting deviations with respect to the most commonly used theoretical models are observed.

MEASUREMENT OF FORWARD JETS AT RHIC

We present first measurements of forward jet production from p↑ + p collisions at [Formula: see text] GeV, including transverse single spin asymmetries. These asymmetries are expected to be sensitive to spin-correlated transverse momentum in the initial state, which is particularly interesting because it is related to orbital angular momentum in the proton.