Influence of Wind Tunnel Test Duration on Wind Load Factors

Area of Science:

• Aerospace Engineering
• Civil Engineering
• Structural Engineering

Background:

• Accurate estimation of peak pressure coefficients from wind tunnel tests is crucial for determining design wind effects.
• Uncertainty in these estimations, influenced by record length, can impact structural safety and design efficiency.

Purpose of the Study:

• To present a method for calculating the uncertainty in peak pressure coefficient estimation from wind tunnel test records of varying lengths.
• To assess how this uncertainty influences design wind effects for different structures and testing facilities.
• To provide guidance on minimum required lengths for pressure records in wind tunnel studies.

Main Methods:

• A novel method is proposed to quantify the uncertainty associated with peak pressure coefficient estimations.
• The method is applied to analyze time series data from five categories of pressure coefficients outlined in ASCE 7-10.
• The investigation considers various record lengths and their impact on calculated design wind effects.

Main Results:

• The proposed method is applicable to diverse structures and civil engineering aerodynamic testing facilities, including large-scale ones.
• For typical civil engineering wind tunnels, design wind effects derived from 10-second tests (approx. 6 min prototype) are only about 5% larger than those from 100-second tests.
• Shorter test durations show a minimal, quantifiable increase in estimated design wind effects.

Conclusions:

• The developed method effectively calculates uncertainty in peak pressure coefficient estimation.
• Short-duration wind tunnel tests (e.g., 10 seconds) provide reliable estimates for design wind effects, with minor increases in calculated values compared to longer tests.
• The findings offer practical guidance on selecting appropriate minimum lengths for pressure records in wind tunnel aerodynamic testing.