Boeing’s Sustainable Aircraft Concept Completes First Wind Tunnel Tests

https://defensemirror.com/news/39175/Boeing___s_Sustainable_Aircraft_Concept_Completes_First_Wind_Tunnel_Tests

#Boeing #SustainableAviation #X66 #FlightInnovation #NASA #GreenAviation #FutureOfFlight #WindTunnelTesting #AerospaceTech

Boeing’s Sustainable Aircraft Concept Completes First Wind Tunnel Tests

https://defensemirror.com/news/39175/Boeing___s_Sustainable_Aircraft_Concept_Completes_First_Wind_Tunnel_Tests

#Boeing #SustainableAviation #X66 #FlightInnovation #NASA #GreenAviation #FutureOfFlight #WindTunnelTesting #AerospaceTech

Derecho-Induced Skyscraper Damage

Derechos are short-lived, intense wind storms sometimes associated with thunderstorms. Last spring, such a storm passed through Houston, leaving downtown skyscrapers with more damage than a hurricane with comparable wind speeds. Now researchers believe they know why a derecho’s 40 meter per second winds can badly damage buildings built to withstand 67 meter per second hurricane winds.

In surveying the damage to Houston’s skyscrapers, the team noted that broken windows were concentrated in areas that faced other tall buildings. In a wind facility, the team explored how skyscrapers interfered with each other, based on their separation difference. They looked both at conditions that mimicked a hurricane’s winds as well as the downbursts — strong downward wind bursts — that are found in derechos.

The researchers found that downbursts in between nearby buildings caused extremely strong suction forces along a building’s face — even compared to the forces seen with higher hurricane-force winds. Currently, these buildings are designed for hurricane-like conditions, but the team suggests that — at least in some regions — designers will need to take into account how downburst wind patterns affect a skyscraper, too. (Image credit: National Weather Service; research credit: O. Metwally et al.; via Ars Technica)

#derecho #downburst #engineering #fluidDynamics #meteorology #physics #science #wind #windTunnelTesting

Wind plays a major role in cycling, since aerodynamic drag is the greatest force hampering a cyclist. In road racing, both individual cyclists and teams use tactics that vary based on the wind speed and direction. Crosswinds — when the apparent wind comes from the side in the cyclist’s point of view — are some of the toughest conditions to deal with. In races, groups will often form echelons to minimize the group’s overall effort in a crosswind. Alternatively, racers looking to tire their competitors out will position themselves on the road so that the rider behind them gets little to no shelter from the wind; this is known as guttering an opponent.

In this study, researchers put a lone cyclist in a wind tunnel and measured the effects of crosswind from a pure headwind to a pure tailwind and every possible angle in between. From that variation, they were able to mathematically model the aerodynamic effects of crosswind on a cyclist from every angle. With rolling resistance (a cyclist’s second largest opposing force) included, they found relatively few conditions where a crosswind actually helped a cyclist. Most of the time — as any cyclist can tell you — hiding from the wind is beneficial. (Image credit: J. Dylag; research credit: C. Clanet et al.)

Related topics: The physics of the Tour de France, how the peloton protects riders aerodynamically, track cycling physics, and a look inside wind tunnel testing bikes and cyclists

Catch all of our ongoing Olympics coverage here.

https://fyfluiddynamics.com/2024/08/paris-2024-cycling-in-crosswinds/

#crosswinds #cycling #drag #dragReduction #echelon #fluidDynamics #olympics #Paris2024 #physics #science #sports #windTunnelTesting

Scientists have long suspected that birds save energy by following a leader — think of the V-shaped flight formation used by geese — but a new study captures that savings directly. The team studied starlings, flying singly or in groups of two or three, in a special wind tunnel. Each bird wore a tiny backpack with sensors and lights that captured its motion and helped researchers identify it individually in videos. And, using before and after metabolic measurements, the researchers could pin down exactly how much energy each bird used when flying.

They found that birds who spent most of the flight in a “follower” position used up to 25% less energy than they did when flying solo. That’s a major incentive to follow someone else. Interestingly, they also found that the most efficient solo fliers were the birds most likely to take on the “leader” position. The team notes that these “leaders” tend to use a lower wing-flapping frequency, but a full explanation of how they save energy will require a follow-up study. (Image credit: R. Gissler and S. Hao; research credit: S. Friman et al.; via Physics World)

https://fyfluiddynamics.com/2024/07/saving-energy-by-following-a-leader/

#biology #birds #drafting #experimentalFluidDynamics #flappingFlight #fluidDynamics #physics #science #windTunnelTesting