This document is an extract from a study of air velocities and trajectories around a planned building in France. The aim of the study is to verify the feasibility of implementing wind power systems for the building’s electricity production, then to propose alternatives for optimizing their performance, and to evaluate and assess the evolution of majority winds on site around the building in question.

The defense district has a high density of buildings per m2, giving rise to numerous aeraulic masks. This characteristic of the district is of great importance in the evolution of airflow.

For this simulation, a large proportion of the buildings close to the project were modelled in order to take into account the particular conditions of the site, which is a specific location with a high density of dwellings and tall buildings. Additional precision was added in order to obtain accurate results with regard to aeraulic masks.

The external CAD model produced shows the simplified geometry of the site and its surroundings within a 400m radius. It is based on the plans supplied.

Study results for a north-easterly wind

For a north-easterly wind, a number of specific aeraulic phenomena can be observed. For this wind direction, air speeds at ground level are of the order of 1.5 to 2 m/s.

The wind tends to blow towards Square Henri Regnault for two reasons:

The restriction of airflow between the Les Dauphins residence and the Gambetta tower gives rise to a Venturi effect.
The wind passing under the Boulevard Circulaire tends to redirect the air towards the square.

Simulation of the wind around the building

Study of ground air speeds

For a south-westerly wind, a number of specific aeraulic phenomena can be observed. For this wind direction, ground air speeds are of the order of 1.5 to 2 m/s close to the building’s south façade.

We note that the wind tends to blow between the project building and the Les Dauphins residence.

The simulation results show that the restriction of air flow between the Les Dauphins residence and the south-west building of the square gives rise to a Venturi effect accelerating the air towards the project building.

Air velocities at 40 m above ground are of the order of 1.5 m/s.

The simulation shows that for this wind direction, the Les Dauphins residence provides a sufficient aeraulic mask to protect a large part of the project building.

This aeraulic mask greatly reduces velocities when approaching the roof. Therefore, no overspeed due to wall separation was observed.

Conclusion on building morphology

Digital simulation offers new perspectives for design offices. This makes it possible to foresee a large number of scenarios and consequently to control all the unforeseen events linked to a bad design. In the case of new buildings, renovations or new layouts, multiphysics modelling enables us to take into account all the phenomena at the origin of the thermo-aeraulic flows that contribute to the building’s thermal insulation.

Thanks to its calculation servers, EOLIOS models can be simulated in their entirety with great precision in a very short space of time. What’s more, EOLIOS’ experience in general aeraulics enables our team to propose innovative and relevant solutions in the aeraulics field. Implementing CFD simulations in your design process means calling on experts in fluid mechanics, thermal engineering and numerical simulations to ensure that no problems arise in the future.

Our EOLIOS engineers benefit from a strong experience in the audit by bringing directly their expertise in order to optimize the resolution of the various problems.

Their cutting-edge equipment enables direct and distinct measurements, guaranteeing an assessment of the site, equipment and materials, and if necessary, a thermal expertise including thermal bridges, heat loss and loss of performance of air-conditioning systems.

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Wind study – La Défense

Wind study – La Défense

In a few words

Air & Wind