Eddy Dissipation Rate (EDR) – 一個同turbulence intensity 有關既詞彙!

Reference: https://www.flyingmag.com/how-do-you-interpret-an-eddy-dissipation-rate/

EDR quantifies turbulence for a specific aircraft, and it’s not a measure of the likelihood of turbulence—just the intensity.

ERR – Eddy Dissipation Rate 的三件事

1. refer to specific aircraft (type specific)
2. describe the intensity of turbulence
3. 同turbulence 發生機率無關

EDR 愈高代表Turbulence 對果類機既影響愈大

EDR is an observed or forecast value that is between 0 and 1 with 0 representing perfectly smooth air and 1 implying supercell thunderstorm level of mixing.

Note:

EDR is an aircraft-independent meteorological field expressed in m²/s³ (meters squared per seconds cubed). Simply put, an atmosphere that causes eddies to dissipate rapidly is one that is likely turbulent. Most importantly, EDR is not a measure of the likelihood of turbulence, just the intensity.

EDR 係 aircraft type specific information

EDR is not a “one size fits all”. This means an EDR value of 18 may produce moderate turbulence for a Cirrus SR20, but will be considered light turbulence for a Boeing 737.

溫故知新 – Other background knowledge :

What we should do when come across turbulence in flight?

When confronted with moderate or greater turbulence while in flight, the first response is to slow down below the aircraft’s maneuvering speed (a.k.a turbulence penetration speed)

Who define this “turbulence penetration speed” / What factor affect the “turbulence penetration speed”?

Maneuvering speed is directly dependent on the aircraft’s weight. In other words, the heavier the aircraft, the higher the maneuvering speed.

Why we need to reduce to (fly at) the so called “aircraft’s maneuvering speed”?

By reducing airspeed, the goal is to reduce the forces (or load) on the aircraft parts that could fail as the aircraft accelerates and decelerates in moderate or greater turbulence. (吾會整爛隻機, 但又夠speed 去generate sufficient lift for the acft to fly through the turbulence area)