Movable Roof Sectors: Revolutionizing Automotive Aerodynamics Without Sacrificing Comfort

Overcoming the classic compromise between style, aerodynamic efficiency, and interior space is a constant pursuit in automotive design. A groundbreaking solution has emerged: movable roof sectors. This innovative design, patented by Francesco Fiumara, benefited from rapid aerodynamic validation through Nablaflow’s AeroCloud platform. AeroTarget, with Giacomo Gentile’s CFD expertise, provided concrete numerical evidence supporting the design’s potential.

The Core Challenge: Style vs. Space vs. Aerodynamics

The automotive industry has long struggled with a fundamental compromise between design elements. Stylish, streamlined coupes and sedans typically sacrifice rear passenger space, while vehicles prioritizing interior comfort often suffer from reduced aerodynamic efficiency. This challenge prompted the development of an innovative solution: movable roof sectors that adapt based on passenger occupancy. This technology addresses the persistent design conflict that has challenged automotive engineers for decades.

Today’s automotive market demands attention to three fundamental elements:

• Performance - Aerodynamics significantly impacts fuel consumption in traditional vehicles and driving range in electric vehicles

• Space- Vehicles must provide comfort and practicality for all passengers

• Style- A car’s design heavily influences market appeal and can make certain models timeless

While iconic cars like the Mercedes SL, Jaguar E-Type, or Porsche 911 have achieved legendary status through distinctive styling, this often comes at the expense of interior space, particularly for rear passengers.

The Impact of Rear Design on Aerodynamics

The rear portion of a vehicle plays a crucial role in aerodynamic performance. Elements such as tail height and the angle of the rear window significantly affect airflow separation and wake turbulence. This is where the expertise of Giacomo Gentile from AeroTarget proved invaluable, applying advanced CFD knowledge to analyze different vehicle configurations.

Three different configurations of the same car were analyzed using Nablaflow’s AeroCloud platform:

• “normal car” with adequate space for all passengers but higher drag

• " aero/style aerocar" with a lower roof and tail, reducing interior space but improving style and aerodynamics

• “movable roof sector car” combining aerodynamic efficiency with adaptable passenger space.

How Movable Roof Sectors Work

The movable roof sector concept, patented by Francesco Fiumara, is elegantly simple: when rear passengers enter the vehicle, the roof sectors move upward to provide comfortable headroom. When the rear seats are unoccupied, the roof sectors remain in the closed position, maintaining the car’s streamlined profile.

The wake behind a vehicle is the primary factor affecting drag resistance. A more aggressively sloped roofline reduces the size of the turbulent area (wake) behind a vehicle. A smaller wake means there’s less low-pressure air pulling the vehicle backward, thereby decreasing aerodynamic drag. Through the collaboration between Nablaflow and AeroTarget, advanced CFD simulations have shown a remarkable 5% total drag reduction when comparing the closed-sector configuration to the standard design – a significant improvement in automotive aerodynamics.

The Impact on Efficiency and Sustainability

This innovation has far-reaching implications, particularly as automotive manufacturers work to meet increasingly stringent emissions targets set by regulatory bodies like the European Union. By maintaining optimal aerodynamics during the majority of driving time (when rear seats are unoccupied) and only sacrificing efficiency when additional passenger space is needed, vehicles can achieve better overall efficiency.

For electric vehicles, this could translate to meaningful range improvements. Cars have grown larger over time, partly to accommodate safety features but also to provide more interior space. The movable roof sector concept, offers a path toward more efficient designs without compromising comfort.

From CFD to Reality

The analysis of this design has been facilitated through the use of Nablaflow’s AeroCloud cloud-based CFD simulation platform. The expertise provided by Giacomo Gentile of AeroTarget proved crucial in interpreting and optimizing the simulation results. Complete simulation results were available in hours, reducing the overall testing period to just 2-3 days, and allowing for rapid iteration and refinement.

One key design consideration is that the movable sectors must create a sealed separation between the interior and exterior of the vehicle, distinguishing this solution from traditional sunroofs or convertible tops.

The Future of Modular Vehicle Design

While current industry resources focus predominantly on electric powertrain development, the collaborative research between Nablaflow, AeroTarget, and Fiumara demonstrates substantial efficiency gains still achievable through advanced aerodynamic optimization. Modern cars have grown larger and heavier over time, but the movable roof design offers a different approach—maintaining comfort and aerodynamic efficiency in a more compact package. For EVs, where charging remains a challenge, these aerodynamic improvements could significantly boost range and battery consumption.

Conclusion

The movable roof sector patent, created by Fiumara and tested with advanced simulation tools, tackles a long-standing challenge in car design—balancing style, aerodynamics, and comfort. By adapting in real-time to how many people are in the car, it gives designers more freedom without sacrificing efficiency. As the auto industry moves faster toward electrification, smart innovations like this will make a real difference, helping cars perform better while still looking great and feeling comfortable to drive.