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CFD Analysis of Wind Loading Pressure Equalisation on the Cavity for Sample Project Cladding System


This analysis is a comprehensive exploration of Computational Fluid Dynamics (CFD) analysis, focusing on wind loading pressure equalisation dynamics within the cladding system. With a specific emphasis on the cavity, a critical element in preventing air and water ingress, the analysis integrates theoretical calculations, literature review, and advanced CFD simulations to precisely quantify the degree of pressure equalisation. The primary goal is to provide actionable insights for refining the design and optimising the performance of the cladding system.

Cladding System:

The cladding system includes diverse materials, such as Colourbond sheet metal. Characterised by unsealed gaps at ends, joints, and openings, creating a rainscreen effect, the system places heightened importance on the cavity as the primary air-seal weatherline. This analysis meticulously investigates pressure loss through the cladding gap onto the cavity, with a specific focus on the interface between the cavity and the structure.

Theoretical Calculation:

A theoretical approach is employed to estimate pressure loss through the cladding gap, utilising a simplified formula. The K factor, derived from various sources, is anticipated to yield a pressure reduction of less than 50% of the original wind loading pressure.

Literature Review:

Insights gleaned from reputable studies, notably those from the Centre for Window & Cladding Technology and Connell S. Miller's PhD thesis, substantiate pressure equalisation factors for cladding systems. The collective findings underscore a consistent reduction of less than 73% in wind loading pressure.

CFD Analysis:

The cornerstone of this report is the meticulous CFD analysis, where simulations scrutinise airflow within the cavity during gusty winds in a standard building and cladding system. Employing the turbulence model and a highly detailed mesh study, this advanced methodology enhances precision and provides a nuanced understanding of pressure dynamics.


The CFD simulations reveal a pressure equalisation factor for the cavity, ranging from 65% to 75% during gusty winds. These results underscore the efficacy of pressure equalisation within the cladding system.

Pressure contour and velocity vectors in cavity

Pressure contour and velocity vectors in cavity


In conclusion, the CFD analysis stands as a pivotal tool in understanding and optimising wind loading pressure equalisation within the cladding system. The findings accentuate the critical role of the cavity, guiding meticulous design considerations for withstanding wind loads and preserving the building envelope's integrity. This report not only contributes valuable insights but serves as a foundation for future design refinements, ensuring the robust performance of the cladding system.

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