Everything about Transonic totally explained
Transonic is an
aeronautics term referring to a range of velocities just below and above the
speed of sound (about
mach 0.8–1.2). It is defined as the range of speeds between the
critical mach number, when some parts of the airflow over an aircraft become
supersonic, and a higher speed, typically near
Mach 1.2, when all of the airflow is supersonic. Between these speeds some of the airflow is supersonic,and some is not.
Most modern
jet powered aircraft spend a considerable amount of time in the transonic state. This is particularly important due to an effect known as
wave drag, which is prevalent in these speed ranges. Attempts to combat wave drag can be seen on all high-speed aircraft; most notable is the use of
swept wings, but another common form is a wasp-waist fuselage as a side effect of the
Whitcomb area rule.
Severe instability can occur at transonic speeds. Shock waves move through the air at the speed of sound. When an object such as an aircraft also moves at the speed of sound, these shock waves build up in front of it to form a single, very large shock wave. During transonic flight, the plane must pass through this large shock wave, as well as contending with the instability caused by air moving faster than sound over parts of the wing and slower in other parts. The difference in speed is due to
Bernoulli's principle.
Transonic speeds can also occur at the tips of
rotor blades of helicopters and aircraft. However, as this puts severe, unequal stresses on the rotor blade, it's avoided and may lead to dangerous accidents if it occurs. It is one of the limiting factors to the size of rotors, and also to the forward speeds of helicopters (as this speed is added to the forward-sweeping (leading) side of the rotor, thus possibly causing localized transonics).
Interesting facts
- At transonic speeds intense low-pressure areas form at various points around an aircraft. If conditions are right (for example high humidity) visible clouds will form in these low-pressure areas as shown in the illustration; these are called Prandtl-Glauert singularities. These clouds remain with the aircraft as it travels. It isn't necessary for the aircraft as a whole to reach supersonic speeds for these clouds to form.
Further Information
Get more info on 'Transonic'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://transonic.totallyexplained.com">Transonic Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |