Wind Storm Loss Estimation Using CFD and Roughness Length Segmentation
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Solution Overview
Problem
Current catastrophe models for estimating economic losses due to wind storms, such as hurricanes, face imprecision in calculating roughness length, which significantly impacts insurance pricing and loss assessments, as they rely on broad land use classifications rather than precise terrain and land use features.
Innovation Solution
The use of imaging data and three-dimensional modeling, combined with computational fluid dynamics simulations, allows for a more accurate estimation of roughness length by simulating wind flow and calculating local wind speeds, enabling a weighted average of roughness lengths and subsequent determination of average annual loss, probable maximal loss, and insurance premium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If broad land use classifications are used to estimate roughness length, then the complexity of the modeling process is reduced, but the measurement precision of roughness length deteriorates
Solution Approach 1:
The patent segments the continuous terrain into discrete elevation zones by comparing terrain elevation data with structure elevation data. This creates multiple roughness length categories (e.g., near-field, mid-field, far-field zones) that are then weighted and combined. This segmentation approach maintains modeling tractability while capturing the spatial variability of roughness length that broad classifications miss.
Solution Approach 2:
The patent applies local quality by assigning different roughness length values to different spatial zones around the structure based on local terrain characteristics. Instead of using a single uniform classification, the model calculates zone-specific roughness lengths weighted by the proportion of each zone, thereby capturing local terrain features while maintaining overall model coherence.
2Measurement precision
If high resolution wind field modeling is implemented, then the measurement precision of wind speeds improves, but the computational resources and time required increase
Solution Approach 1:
The patent performs preliminary action by pre-calculating the roughness length distribution across multiple zones before running the wind field simulation. The terrain is pre-segmented into elevation-based zones and weighted roughness lengths are computed in advance, allowing the subsequent wind field model to use these preprocessed parameters without recalculating them during the simulation, thereby reducing overall computational time.
3Reliability
If terrain and land use features are accurately modeled, then the reliability of loss estimation improves, but the data requirements and processing complexity increase
Solution Approach 1:
The patent extracts only the essential terrain characteristic needed for roughness length estimation - the elevation difference between terrain and structure. Rather than processing complete land use/land cover datasets or detailed terrain models, the method extracts and utilizes solely the elevation data required for zone classification, thereby maintaining reliability while reducing data processing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides a more precise estimation of wind-related losses and insurability, reducing the variability in insurance pricing and improving the accuracy of loss assessments by accounting for specific terrain and land use features.
Implementation Method 1
performing a computational fluid dynamics (CFD) simulation of wind flow through the three dimensional model to determine local wind speed
Implementation Method 2
using the Log Wind Profile equation to calculate roughness length from the local wind speed
Data Source
AI summary
The present invention relates to systems and methods for estimating economic losses from wind storms. Accordingly, provided herein are methods estimating roughness length of an area surrounding a structure, methods calculating local wind speed at a structure, methods of estimating wind pressure on a structure, and methods of calculating the insurability of a structure. Also provided are systems and computer-readable storage media configured for performing the disclosed methods.