Downloaded from https://www.everyspec.com MIL:STD-810D 19 July 1983 TABLE 515 .3-III. ties ed cav tv resonance acoust t i ic test. Parametric Equations for figure515.3-4 I Functional Test Level B. = 20 log(q) + 110 dB (Re$ 20v pa (0,.0002microbar)) I Endurance Test Level B. = 20 log(q) + 2.5 log(H/T) + 110 dB (Ref’20u pa (0.0002 microbar)) 0 75)(7 4 M /7) 2 1/2 = ~;(c.) + (;.i-#/2)1/~ Hz Definitions .. fN . resonance frequency fOr the N mode (where N . 1,2,3,4, etc.) N . mode number C . speed of sound at altitude of flight’(M/S) L . length, radius, of opening exposed to airstream (meters) M .
Mach number A second set of rekonance frequencies shall be identified by using the distance parameter, L, as the depth of the cavity. q = flight dynamic pressure when cavity is open (lbslft2) H . number of operational hours store is flown with cavity open. If H endurance test is not required. T . duration of test in hours (minimum T . 1 hour) ., & 5C0 10112 2000 FIGURE 515.3-4. _Cavitvresonance Acetic test level.a M3THOD 515.3 19 July 1983 515.3-12