DIRD_31-DIRD_Detection_and_High_Resolution_Tracking_of_Vehicles_at_Hypersonic_Velocities.pdf

UNCLASSIFIED / / POR OUPPICTRE VS Cntr Defense Intelligence Reference Document Pek el Defense Futures 20 November 2010 ICOD: 30 August 2010 DIA-08-1012-001 Detection and High Resolution Tracking of Vehicles at Hypersonic Velocities UNCLASSIFIED / /S02.05h6birEGr Oh

UNCLASSIFIED / / PO ROP PECEiie=UGE-Oliineas Detection and High Resolution Tracking of Vehicles at Hypersonic Velocities The Defense Intelligence Reference Document provides nonsubstantive but authoritative reference information related to intelligence topics or methodologies. Prepared by: Author: (b)(6) (U) COPYRIGHT WARNING: Further dissemination of the photographs in this publication is not authorized. This product is one of a series of advanced technology reports produced in FY 2010 under the Defense Intelligence Agency, |(b)(3):10 USC 424 Advanced Aerospace Weapons System Applications (AA…

UNCLASSIFIED / (PORoOPPtCERE-UGE-ONEY Contents i Cg) coye |e [o:4| ©) o penne nr an 1 Chapter 1: Theory Governing Objects in FLIQNC....... eect cette reer eee ee eee nett eee ee eee nets 3 Subsonic FIOW ANd Drag .....ccccceeccccee cece eee eee eee eee eee eH SEE ODE E REESE SRS EES EEE E EEE ESSE EEE SEE DEERE EDS 3 SUPErSONic FLOW oo... ceecceee eee eee ne ee EEE EHEC DEAE DE EE DE EDS EERO EEDA E ERAT ERSTE ODEO REE EROS ER CES EEE E EAE 6 Chapter 2: Hypersonic Compressible FIOW Theory... cccccceceeeesere estes eases seed enaeaetennenaes 10 Chapter 3: Detection TeEchnologi€S ........cccccces…

Figures Figure 1. Figure 2. Figure 3. Figure 4. Figure 5, Figure 6. Figure 7. Figure 8, UNCLASSIFIED / /P@R-OPPICRRE USE ORT Boundary Layer Development in Subsonic Flow about a Projectile.............ccccce 4 Subsonic Flow Past @ Projectile. 0... cccccsseseseeceeeeseseeeveueseseeeueeecaeueusugeseueeeasaens 5 Strouhal Frequency as a Function of Reynolds Number for Flow over a Circular Cylinder, .....cccccccceccesecesesuecseeseuenceueeeseceeseeeeeeesueasauacesuetetavavavatenannersras 6 Supersonic Flow Past a Wedge-Shaped Body........ccccccssseesuusseceeeuseueeveeveeeveseeness 8 Supersonic Flow P…

UNCLASSIFIED / /#@R-0FFIGHA-6GE-ONE Introduction An object is supersonic when its speed through the atmosphere is greater than the local speed of sound. The Mach number is defined as the speed of the object divided by the local speed of sound. For Mach numbers greater than 1 (supersonic flow), shock waves develop in the flowfield and near the surface of the object due to the air’s compressibility. Traditionally, the lower Mach number limit for the so-called hypersonic speed regime is about Mach 5 (1.7 km/sec). "Low hypersonic” values range between Mach 5 to about Mach 10, while “high hypersoni…

UNCLASSIFIED / /(P@R-OPEECEREUSE-OnNE There are a number of different techniques available to detect hypersonic objects and to determine their position, velocity, and trajectory. These detection methods can be broadly divided into electromagnetic, optical, and acoustic/seismic methods. Each method relies on the properties of the surface of the object to reflect incident radiation or upon the properties of the hot ionized gases caused by the bow shock and entrained into the object’s wake. The theory of external fluid flow around objects in subsonic, supersonic, and hypersonic regimes will be re…

UNCLASSIFIED / /fORoOPPICTAL USE Oner Chapter 1: Theory Governing Objects in Flight Many of the detection technologies for hypersonic aircraft are based on the properties of the air flow around the object. The fluid mechanics affecting supersonic and hypersonic aircraft are well described in textbooks on compressible flow by J.D. Anderson;?3 subsonic flow, including the affect of boundary layers, is covered in the textbook by F. M. White.4 Hypersonic flow usually refers to the regime where objects are moving faster than Mach 5, but technically refers to the Mach range where pressure, temperatu…

UNCLASSIFIED / (POR OPPICTR EUS Otay viscous forces VD Re = EE (3) inertial forces v In this expression, V is the velocity of the projectile, D is its effective diameter, and vy is the kinematic viscosity of the fluid. As flow passes over the projectile in Figure 1, viscous forces are especially strong near the surface where the velocity changes from zero at the surface of the projectile to the free stream velocity. Direction of Flow _— Streamlines Boundary Layer 1 1 ' ' 1 -— Figure 1. Boundary Layer Development in Subsonic Flow About a Projectile. The region where this transition in velocity …