PIV MEASUREMENTS OF TWO VELOCITY COMPONENTS AT PEDESTRIAN LEVELS IN SIMPLIFIED URBAN CANOPY

Abstract

The rare weak and strong wind-speed phenomena at the pedestrian level are mostly unpredictable because of the complex velocity fields within an urban canopy. In this study, therefore, two velocity components within a simplified urban canopy layer were measured using time-resolved particle image velocimetry (PIV) to scrutinize the instantaneous and statistical characteristics of pedestrian-level winds (PLWs). The new laser-camera system realized by inserting a laser optics system into a focal block could successfully capture the flow fields within an urban-like array, which enabled us to understand the aerodynamic effects of simplified block arrays on the PLWs.