Synopsis

Pitch-Perfect Corrections for Turbulence

Physics 16, s86
A new system could allow autonomous aircraft to correct the pitch of their wings to account for gusts of wind that abruptly change lift in real time.
G. Sedky et al. [1]

For airliners, encountering turbulence usually results in no more than spilled drinks and startled passengers. But for small aircraft with less inertia—such as drones and future air taxis—sudden air movements can be catastrophic. What’s more, these aircraft are expected to operate in urban environments, where air currents are less predictable. There is therefore a growing need for automatic systems that can quickly and safely steady an aircraft hit by a wind gust. Now Girguis Sedky at the University of Maryland, College Park, and colleagues have demonstrated a system that compensates for sudden air movements by varying the pitch of an aircraft’s wings [1].

The team focused on correcting for the effects of winds that blow upward across an aircraft’s wings. Such gusts are dangerous because they can cause the airflow to separate from the wings’ upper surfaces—an aerodynamic stall—leading to an abrupt loss of lift. Altering the pitch of the wings can mitigate the effect, but making the right real-time correction is difficult, as pitch changes can induce additional forces that depend on the position of the wings’ axis of rotation.

G. Sedky et al. [1]
A model wing moves from right to left in a water tank. Upon encountering a vertical current, the wing’s pitch is modified automatically to maintain a constant reading on a force sensor.

The team’s automatic feedback system constantly monitors a wing’s lift, comparing the actual value, measured using a force sensor, to the desired one. Any divergence between the two numbers triggers a pitch change. The researchers tested their system by immersing a wing in a water tank and driving it horizontally through an upward-directed current. When the rotation axis was at the wing’s center, the system successfully maintained the wing’s lift in real time. Sedky is now looking at ways to prevent stalling by emulating the wing feathers of birds.

–Marric Stephens

Marric Stephens is a Corresponding Editor for Physics Magazine based in Bristol, UK.

References

  1. G. Sedky et al., “Experimental mitigation of large-amplitude transverse gusts via closed-loop pitch control,” Phys. Rev. Fluids 8, 064701 (2023).

Subject Areas

Fluid Dynamics

Related Articles

Ocean Currents Resolved on Regional Length Scales
Computational Physics

Ocean Currents Resolved on Regional Length Scales

Using a detailed simulation, researchers reveal how climate change will affect the regional dynamics of the conveyor-belt-like circulation of water through the Atlantic Ocean. Read More »

A Slight Curvature Gives Pebbles an Impacting Edge
Fluid Dynamics

A Slight Curvature Gives Pebbles an Impacting Edge

Pebbles that are slightly curved—rather than completely flat—exert the highest impact forces when dropped onto a watery surface. Read More »

Predictions for Small-Scale Turbulence
Fluid Dynamics

Predictions for Small-Scale Turbulence

A statistical tool tests the long-held assumption that small-scale turbulence is isotropic. Read More »

More Articles