Regards, RE: Supersonic speed Grue (Aeronautics) 20 Nov 03 16:00 This is a significant change compared to a ratio of 0.9563 at M=0.3. For example, at M=1, the density ratio (rho/rho stagnation) is 0.6339 or roughly 63% at state 2 when compared to state 1. You must have a state 1 density and a state 2 density. You may not arbitrarily just increase the air density and then assume it to be constant. As stated earlier, when dealing with the trans/supersonic regime, the change in density MUST be accounted for. It is then no longer a fluid and does not follow Bernoulli.Īgain, where do you come up with this? You're saying that compressed (pressurized) air is not a fluid? Explain to me how air at SSL is "compressed" compared to that at 50,000 ft, but each remains a "fluid".Īs for making "adjustments" to Bernouli, I'm not sure what you mean. the air speeds up to reach the speed of sound, and compresses. How can you say this? Where did you go to school? Air (or any other gas for that matter), although behaves as a fluid, is extremely susceptable to compressibility effects! "Air acts as a fluid and therefore is incompressable at speeds below the speed of sound." RE: Supersonic speed aerobab (Aerospace) 20 Nov 03 09:51 If you would like to see some pics of various aircraft flying in the transonic range then go to. In the early days of high speed flight, Mcrit was a closely guarded secret, and the guesstimate of 0.8 was often used. The actual figure would depend on the aircraft. The figure of M=0.8 is a guess at the speed at which Mcrit is reached. This range of flight is called the transonic range, and presents problems for aircraft designers. Aircraft flying at speeds between where the airflow reaches Mcrit, and becomes fully supersonic are of most concern. The point at which this first occurs on an aircraft is called the aircraft's critical Mach number (Mcrit). It is then no longer a fluid and does not follow Bernoulli. The atmosphere follows those principles when a body is travelling through it until the airflow reaches the speed of sound.Īir acts as a fluid and therefore is incompressable at speeds below the speed of sound but when a body travels at speeds approaching the speed of sound, the air speeds up to reach the speed of sound, and compresses. Bernoulli's principle is valid for all fluids.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |