Planetary Boundary-Layer Modelling and Tall Building Design

Area of Science:

• Meteorology
• Structural Engineering
• Atmospheric Science

Background:

• Planetary boundary layer (PBL) flow characteristics significantly impact tall structure design.
• Current building codes rely on outdated PBL models from the 1960s-1970s, differing from sophisticated contemporary models.
• Contemporary PBL models yield significantly different PBL heights compared to classical and building code approaches.

Purpose of the Study:

• To propose a simple method for estimating friction velocity and PBL height.
• To provide a more accurate basis for tall structure design by reconciling PBL modeling discrepancies.
• To encourage collaboration between meteorologists and structural engineers.

Main Methods:

• Development of a simple estimation method for friction velocity and PBL height.
• Analysis of contemporary PBL models versus classical asymptotic similarity approaches.
• Evaluation of flow velocity components and veering angles at high altitudes.

Main Results:

• Contemporary PBL models estimate heights approximately half those from classical methods and one order of magnitude larger than building codes.
• A simple method is proposed for estimating friction velocity and PBL height based on surface roughness and geostrophic wind speed.
• The cross-surface stress velocity component and veering angle are found to be negligible at 800m.

Conclusions:

• Existing building codes use inadequate PBL models for modern engineering needs.
• The proposed simple method offers a practical approach to improve PBL height and friction velocity estimations.
• Further dialogue between atmospheric scientists and structural engineers is crucial for advancing tall structure design.