ITS Berkeley

Latin America experiences both high road traffic mortality and extreme heat, which have been shown elsewhere to be interrelated. However, few studies have examined this association in Latin America—one of the world’s most urbanized, fastest-motorizing regions, with a high share of vulnerable road users—and even fewer have analyzed multiple cities across diverse climates and urban settings. Leveraging ambient temperature and road traffic mortality data (2000–2019) from 272 cities in six Latin American countries, we conducted a time-stratified case-crossover study. On the basis of over 1.9...

Linear global stability analysis is performed on a laminar separation bubble formed dueto surface waviness. The eigenspectrum shows a globally unstable mode, responsiblefor the three-dimensionalisation of the bubble, and a family of low-frequency globallystable modes. An adjoint sensitivity analysis shows high sensitivity of the stable modesupstream of the bubble’s reattachment point. Direct numerical simulation (DNS)alongside with a linear impulse response analysis are performed. DNS shows that, whentransition occurs due to self-excited mechanisms, low-frequency upstream propagatingwaves...

The importance of wavepackets in the generation of mixing noise in twin jets is expected by extrapolation of the insights previously obtained from the study of single isolated jets. This work presents wavepacket models for supersonic round twin jets operating at perfectly-expanded conditions, computed via plane-marching parabolized stability equations based on mean flows obtained from the compressible RANS equations. High-speed schlieren visualizations and non-time-resolved PIV measurements are performed to obtain experimental datasets for validating the modelling strategy. The RANS...

Fluid motion, especially at relatively high Reynolds numbers, often presents non-stationary dynamics characterized by the evolution of the statistical description of the flow and its fluctuations over time, which may arise from external changes in the flow configuration or from the presence of intermittent or transient physical processes. Variational mode decomposition (VMD) is a time–frequency analysis framework that separates a scalar signal into independent amplitude- and frequency-modulated components, each characterized by a finite frequency bandwidth. This paper extends the VMD with...