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Aerodynamic Equilibrium and Stability in Ventilation and Air Quality Control of Complex Urban Tunnels

Other Titles
Aerodynamic Equilibrium and Stability for Air Quality Management in Complex Urban Tunnels
Author
Tan, Zhen; Gao, H. Oliver
Abstract
Modern urban vehicular tunnels generally have a branched structure and complex nonlinear aerodynamics. We established and analyzed the 1-D aerodynamic equations and pollutant dispersion model in such bifurcate hydraulic networks. To design a tractable model that captures system complexity, we proposed a novel piecewise-affine (PWA) approximation for the flow-dependent local pressure-loss coefficients at tunnel junctions. This enables us to model the flow system via first-order ordinary differential equations (ODEs) with piecewise-quadratic polynomials. We proved a fundamental and easily verifiable sufficient condition for the uniqueness and stability of the steady-state solution of each ODE piece. We also demonstrated via a numerical study that for the entire system (across different ODE pieces) there may exist multiple stable steady-state solutions, which can lead to different CO concentration distributions in the system. Our study provides a systematic modeling tool and a theoretical foundation for air quality management in complex tunnels.
Description
Final Report
Sponsorship
U.S. Department of Transportation 69A3551747119
Date Issued
2019-03-10Subject
complex urban tunnels; air quality management; ventilation; nonlinear system; stability
Rights
Attribution 4.0 International
Rights URI
Type
report
Accessibility Feature
alternative text; captions; reading order; tagged PDF
Accessibility Hazard
unknown
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Except where otherwise noted, this item's license is described as Attribution 4.0 International