Survey of Aerodynamic Drag Reduction at High Speed by Energy Deposition

Abstract

A selected survey of aerodynamic drag reduction at high speed is presented. The dimensionless governing parameters are described for energy deposition in an ideal gas. The types of energy deposition are divided into two categories. First, energy deposition in a uniform supersonic flow is discussed. Second, energy deposition upstream of a simple aerodynamic body is examined. Both steady and unsteady (pulsed) energy deposition are examined for both categories, as well as the conditions for the formation of shock waves and recirculation regions. The capability of energy deposition to reduce drag is demonstrated experimentally. Areas for future research are briefly discussed. Nomenclature A = cross-sectional area C D = drag coefficient c p = specific heat at constant pressure D = diameter of body d = diameter of filament G,G = spatial distribution functions for energy deposition I = impulse L = streamwise length ' = characteristic length M = freestream Mach number _ m = mass flow rate P = power p = pressure Q = energy added per unit volume per time Q o = magnitude of energy deposition (energy per unit volume per time) Q T = energy deposited in V in time interval e q = energy added per unit mass per time q o = magnitude of energy deposition (energy per unit mass per time) q T = energy per mass deposited in V in time interval e R = gas constant for air T = temperature T = temporal distribution function for energy deposition U = freestream velocity V = volume v = velocity = f = 1 = ratio of specific heats E f = energy added e , i , L = dimensionless time scales ", " 0 = energy deposition parameters = efficiency of energy deposition = density $ = ratio of energy added to energy required to choke the flow = dimensionless time parameter e = duration of energy pulse Subscripts f = filament 1 = freestream I. Overview I N RECENT years, there has been intense activity in developing a fundamental understanding and practical applications of flow control at high speed using energy deposition. This interest is reflected in numerous conferences and workshops, including the Weakly Ionized Gas Workshops [1-8], the St. Petersburg Workshops [9-12], and the Institute for High Temperatures Workshops [13][14][15][16][17][18][19]. The scope of this research is broad. It encompasses a wide variety of energy deposition techniques (e.g., plasma arcs, laser pulse, microwave, electron beam, glow discharge, etc.) and a wide range of applications (e.g., drag reduction, lift and moment enhancement, improved combustion and mixing, modification of shock structure, etc.).The objective of this paper is to provide a selective survey of research on aerodynamic drag reduction at high speed using energy deposition. The research is reviewed principally from the viewpoint of ideal gas dynamics to elucidate the thermal effects of energy deposition on supersonic flow. In general, nonideal gas effects are not considered (except insofar as they naturally occur in the experiments cited herein) and are the topic of a future survey.The remainder of this paper is d...

Conceptual study on non-ablative TPS for hypersonic vehicles

“…Other approaches to the wave drag reduction are to use the focused energy deposition. A wide variety of energy deposition techniques were investigated by laser pulse, plasma arcs, microwaves, electron beams, pulsed detonations or explosions, etc [16][17][18][19][20][21] . When the focused energy is deposited in the upstream region of a blunt body, the extremely hot gas is created instantaneously to push the surrounding gas outward 17 .…”

Nonequilibrium Plasma Aerodynamics

“…For example, possibilities of supersonic flow control (including shock wave attenuation and shock configuration change) by plasma were discussed in [Bletzinger et al, 2005]. Drag reduction at high speed by energy deposition was discussed in paper [Knight, 2008]. Boundary layer separation control by non-equilibrium non-thermal plasma was reviewed in [Zouzou et al, 2006] and [Corke et al, 2010].…”

Shock wave modulation due to discharged plasma using a shock tube

“…Additionally, for the quiet spike, there has been anxiety about the complexity of the system. Lately, the energy deposition technique has attracted attention as a novel method for improving aerodynamic performance for the future of supersonic transportation systems (Tret'yakov et al, 1996, Adelgren et al, 2005, Knight, 2008. Sasoh et al, further emphasized its significance by demonstrating its merits; the gain of both flight power and drag reduction (Sasoh et al, 2010, Kim et al, 2011.…”

“…The baroclinic effect plays a key role in this energy deposition method (Knight, 2008). Therefore, for the application of this method to the development of actual supersonic transportation, the fundamental mechanics of the effect should be elucidated.…”