If You’re Riding in a Taxi These are the Best Two Windows to Have Open
A new airflow study published in the latest issue of science journal, Science Advances, offers some fascinating insights for passengers and drivers alike.
The research paper was led by Dr. Varghese Mathai, a physicist at the University of Massachusetts, Amherst; and three colleagues at Brown University — Asimanshu Das, Jeffrey Bailey and Kenneth Breuer. The scientists used computer simulations to map how virus-laden airborne particles might flow through the inside of a car.
The team simulated a car loosely based on a Toyota Prius driving at 50 miles per hour (80 km/h), with two occupants: a driver in the front left seat and a single passenger in the back right, a seating arrangement that is common in taxis and ride shares and that maximizes social distancing.
Now the best scenario is to have all windows open, while having all windows closed is the worst. For people in colder climates where it is currently winter, two open windows may be more practical/realistic. If that’s the case, this scientific research suggests to have the rear left window and front right window open.
This configuration allows fresh air to flow in through the back left window and out through the front right window and helps create a barrier between the driver and the passenger.
“It’s like an air curtain,” Dr. Mathai said. “It flushes out all the air that’s released by the passenger, and it also creates a strong wind region in between the driver and the passenger.”
Streamlines computed for the case in which the RL and FR windows are open.
The streamlines were initiated at the RL window opening. The streamline color indicates the flow velocity. Insets show the FR and RL windows colored by the normal velocity. The RL window has a strong inflow (positive) of ambient air, concentrated at its rear, whereas the FR window predominantly shows an outward flow (negative) to the ambient. [source]
Schematic of the model car geometry, with identifiers the FL, RL, FR, and RR windows.
The two regions colored in black represent the faces of the driver and the passenger. Table on the right summarizes the six configurations simulated, with various combinations of fully open and closed windows. [source]
Air change rate (or ACH) calculated on the basis of a residence time analysis for different configurations.
Here, the air change rate is given by 1/τr, where τr is the residence time in hours. Uncertainty estimate is based on the turbulence level. [source]
For those interested, you can read the full research paper here, where you will find additional figures and data along with much more detail into the methodology and findings.
[via New York Times]
