A hybrid numerical approach was used on a three-dimensional cavity at a non-zero inclination angle of the upstream section to reveal the mechanism of self-oscillation and the characteristics of far-field sound field. In this hybrid approach, the unsteady flow physics was captured by a compressible large eddy simulation, and the far-field sound field was calculated by the FW-H integral equation, with the noise source provided by near-field calculation. The mechanism of self-oscillation was revealed based on the instantaneous flow field structure and the pressure inside the cavity. The effects of the position of opening, inclination angle and neck thickness on the frequency and amplitude of the fluctuation pressure inside the cavity were examined. Results showed that the frequency and the amplitude were sensitive to the inclination angle but not to the position of the opening. Under varying neck thicknesses, the fundamental frequencies changed, but the amplitude remained almost constant. The influences of the boundary layer thickness on the amplitude of the fluctuation pressure was also investigated. Results revealed that the oscillation was suppressed once the boundary layer thickness reached a critical value. The findings could provide a reference for a quiet car with a low sunroof buffeting noise.

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The present study aimed to assess a novel modified keyhole fixation technique to treat long head of biceps (LHB) rupture. From May 2015 to July 2017, a total of 9 patients with LHB rupture, decreased muscle strength and pop-eye sign were treated using the keyhole fixation technique combined with extramedullary cortical bone microplate-suspending fixation. Measurements of visual analog scale (VAS) score, elbow joint rotation, flexion strength, the Shoulder Score of the University of California Los Angeles (UCLA) and the Rating Scale of American Shoulder Elbow Surgeons (ASES) score were used to evaluate surgical outcomes prior to and following surgery. The 9 patients with LHB rupture included in the study were followed up for one year post-surgery. The supination and flexion elbow strength of all patients after 1 year was grade V and shoulder pain was relieved. The VAS, UCLA shoulder and ASES scores at one year post-surgery were significantly improved compared with those prior to surgery. In conclusion, modified keyhole fixation for LHB rupture features low difficulty of operation, high safety and reliable fixation, and is therefore a promising novel technique for the treatment of LHB rupture.