Best practice: Calculating snow transport and accumulation for more efficient roof construction

Binkz is a Canadian firm specialising in Computational Fluid Dynamics (CFD) consulting. One of the services offered at Binkz is an application to calculate snow transport and accumulation. This can be used indirectly to design roofs that are both safe and cost-efficient.

Close-up van Cartesius super computer

snowFoam

In the Netherlands snow is not an issue, but in Canada or Scandinavia snow transport by the wind and accumulation can cause severe damage to roofs and buildings. Binkz has developed an application called snowFoam. Ziad Boutanios, Principal Engineer at Binkz, explains how it works: “Our application calculates the snow transport and accumulation resulting from natural snow fall and redistribution by the airflow. As a result it also provides the weight and thickness of snow across a rooftop, around buildings and obstacles or even over a landscape. The application gives our clients a reliable way to calculate the snow weight and compare it to the roof strength. In this way they can identify weak areas in a roof that could fail under excess snow loads.”

ontwerpvoorbeeld van Snowfoam

Example of Snowfoam design

Reliable approach

The new application differs from traditional ways of calculating snow accumulation and weight, which consider the snow and air together as a mixture. “This approach leads to very large errors in situations of snow transport by the air on rooftops and around building structures”, explains Ziad. “Our approach treats the snow and airflow individually and calculates the coupling between them without using empirical formulations. This greatly reduces the calculation errors and leads to more reliable results.” The Binkz application is good news for building with relatively flat rooftops, for instance supermarkets, where snow can accumulate easily. Civil engineers who want to avoid snow problems tend to over-design their roofs, which leads to unnecessary costs. With snowFoam they have a cost efficient tool that helps them to decide how strong their roof should be.

“SURFsara incubated our experiment on its state-of-the-art Cartesius computational cluster and provided daily support for running simulations and post-processing the results."

Fortissimo

To test the application in a High Performance Computing (HPC) environment, Binkz cooperated with VORtech and SURFsara in a Fortissimo project. VORtech is a Dutch company that combines thorough knowledge about mathematical modeling, simulation and computational algorithms with state-of-the-art methods for software development. VORtech provided a fine-grained analysis of the performance of the application in the HPC environment of SURFsara, running in parallel over several dozen processors. “This is necessary because snowFoam requires a lot of computational resources due to the very accurate treatment of the snow and airflow”, says Ziad. “VORtech's analysis allowed us to identify the best possible numerical settings to get the most efficient performance.”

Cartesius and ELvis

Ziad was happy with the support of SURFsara as well: “SURFsara incubated our experiment on its state-of-the-art Cartesius computational cluster and provided daily support for running simulations and post-processing the results. SURFsara also gave us access to their remote visualization cluster ELvis. This allowed us to analyze remotely our simulation results without having to download the tens of gigabytes of data generated by snowFoam for every computational case."

This article is from the annual report 2015