東京大学 · 環境科学
Hongyuan Jia教授の研究室では、都市下の乱流境界層における物質移流のメカニズムを解明するため、風洞実験と数値シミュレーションを融合したアプローチを展開しています。特に、都市形状に起因する不均一なフラックスフットプリントの分布を高精度に評価するための新しいバックワード・オイラー的フットプリントモデルを開発しており、都市環境における大気質評価や環境政策の根拠形成に貢献しています。
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This study developed a backward-Eulerian footprint modelling method based on an adjoint equation for atmospheric boundary-layer flows. In the proposed method, the concentration footprint can be obtained directly by numerical simulation with the adjoint equation, and the flux footprints can be estimated using the adjoint concentration based on the gradient diffusion hypothesis. We first tested the proposed method by estimating the footprints for an ideal three-dimensional boundary layer with diff
Abstract This study addresses the need to investigate footprint function features in urban areas and establish a validation database for numerical methods. Concentration and its flux footprints of a block-arrayed urban model were measured in a wind tunnel with a neutrally stratified boundary layer. The velocity and concentration were simultaneously measured by an X-probe hot wire anemometer and a fast-response flame ionization detector to evaluate the vertical flux. Experimental results highligh
This study investigates the footprint distributions at various measurement positions in an urban array model, considering two incident wind directions, 22.5° and 45°, by a wind tunnel experiment. The airflow velocity and tracer concentration are simultaneously measured by an X-probe hot wire anemometer and a flame ionization detector, respectively, to assess the vertical flux of tracer gas. The experiment findings reveal a unified relationship between footprint distributions and measurement heig
Abstract This study addresses the need to investigate footprint function features in urban areas and establish a validation database for numerical methods. Concentration and its flux footprints of a block-arrayed urban model were measured in a wind tunnel with a neutrally stratified boundary layer. The velocity and concentration were simultaneously measured by an X-probe hot wire anemometer and a fast-response flame ionization detector to evaluate the vertical flux. Experimental results highligh
Abstract This study developed a backward-Eulerian footprint modeling method based on an adjoint equation for the urban environment, which has complex terrains and a high degree of heterogeneity. In the proposed method, the concentration footprint can be obtained directly by simulating the equation, and the flux footprints can be estimated using the adjoint concentration based on the gradient diffusion hypothesis. We first tested the proposed method by estimating the footprints for an ideal three
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