NASA Technical Reports Server (NTRS) 20040090526: An Aerodynamic Assessment of Micro-Drag Generators (MDGs)

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by  NASA Technical Reports Server (NTRS)

AIAA 98-2621
An Aerodynamic Assessment
of Micro-Drag Generators (MDGs)
Steven X. S. Bauer
NASA Langley Research Center
Hampton, Virginia
16th AIAA Applied
Aerodynamics Conference
June 15-18, 1998 / Albuquerque, NM
For permission to copy or republish, contact the American Institute of Aeronautics and Astronautics
1801 Alexander Bell Drive, Suite 500, Reston, VA 20191-4344
AIAA-98-2621
An Aerodynamic Assessment of Micro-Drag Generators
(MDGs)
Steven X. S. Bauer*
NASA Langley Research Center
Hampton, Virginia
A B S T R A C T
Commercial transports as well as fighter aircraft of the future are being designed with very low drag (friction
and pressure). Concurrently, commuter airports are being built or envisioned to be built in the centers of
metropolitan areas where shorter runways and/or reduced noise footprints on takeoff and landing are required.
These requirements and the fact that drag is lower on new vehicles than on older aircraft have resulted in
vehicles that require a large amount of braking force (from landing-gear brakes, spoilers, high-lift flaps,
thrust reversers, etc.). Micro-drag generators (MDGs) were envisioned to create a uniformly distributed drag
force along a vehicle by forcing the flow to separate on the aft-facing surface of a series of deployable
devices, thus, generating drag. The devices are intended to work at any speed and for any type of vehicle
(aircraft, ground vehicles, sea-faring vehicles). MDGs were applied to a general aviation wing and a
representative fuselage shape and tested in two subsonic wind tunnels. The results showed increases in drag
of 2 to 6 times that of a “clean” configuration.
INTRODUCTION It is the objective of this paper to introduce a
unique flow management concept that can be applied
Today’s aircraft are designed with ever to any class of vehicle to change the drag. The
decreasing values of drag to improve fuel economy, concept uses small deployable devices referred to as
increase range, and increase payloads. With MDGs that individually generate small amounts of
decreasing vehicle drag, it is becoming more and more drag, but when deployed in large numbers can
important to consider methods of deceleration. In generate substantial amounts of drag. The micro-drag
addition, both military and commercial aircraft require generators (MDGs) may be thought of as miniature
lightweight, efficient control surfaces. Since 1988, spoilers or speed brakes. During normal operation of
the NASA Langley Research Center has been the vehicle (e.g., during cruise), the devices would not
investigating advanced aircraft control effectors. This be extended into the flowfield and would not increase
research has focused on developing flow management the drag of the vehicle. When actuated, the MDGs
concepts and control concepts that satisfy work in the same manner as stall strips. They are
multidisciplinary design issues for military aircraft. designed to force the flow on a vehicle to separate on
Micro-Drag Generators (MDGs, Ref. 1) were one of the aft-facing side of the device and when spaced
the concepts developed under these programs. In correctly, to allow the flow to reattach before reaching
addition to aerodynamic control effectiveness, MDGs the next device. This allows substantial amounts of
were found to be quite effective at braking and drag to be generated with a simple system of small
aerodynamic deceleration for all vehicles. (micro) devices. The drag generated by a system of
MDGs is expected to be equivalent to that which
would be expected from a single device with the same
projected area as the sum of all the MDG projected
*Aerospace Engineer, Configuration Aerodynamics
Branch, Member AIAA areas. The benefits of having a number of small
devices instead of one large device are: reduction in
weight of actuators, increase in safety because several
Copyright © 1998 by the American Institute of
Aeronautics and Astronautics, Inc. No copyright is MDGs could fail without a large effect on drag
asserted in the United States under Title 17, U.S. generation capability compared to a failure of a single
Code. The U.S. Government has a royalty-free component braking system, and a uniform
license to exercise all rights under the copyright
distribution of load (i.e., drag) which is of particular
claimed herein for government purposes. All
importance for tractor-trailer rigs on ice or rain
other rights are reserved by the copyright owner.
covered roads.
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American Institute of Astronautics and Aeronautics
AIAA-98-2621
Aircraft decelerate by deflecting flaps and M Freestream Mach number
¥
spoilers, wheel brakes, and thrust reversers. Ground N number of MDGs
vehicles (e.g., automobiles, tractor-trailers, buses, q Freestream dynamic pressure, psf
¥
trains, etc.) are also designed for low drag. In this s ridge spacing, inches
case, deceleration is accomplished by using disc or S Reference Area, ft2
drum brakes. Oil tankers, aircraft carriers, and other t width of MDG (or ridge), inches
large ships typically reverse directions on their screws x distance in the streamwise direction, inches
to decelerate or coast (for a mile or more) until their a angle of attack, degrees
momentum is reduced to the point that a tugboat can D Change in force or moment
take over and pilot the ship to a pier. MDG D esignation
XDYZ Designation Format
In addition to deceleration, MDGs could be X MDG Density [L (Low), M (Medium), H
used as a control effector, if applied asymmetrically to (High)]
a vehicle (i.e., applied to one wing or one side of the D Density
fuselage and not the other). Because these devices are Y Size [S (Small), L (Large)]
small (and thus, do not protrude "far" into the Z Type [B (Hemispherical Bumps), P (Vertical
flowfield), they are also attractive for military aircraft Drag Plates)]
survivability. In addition, these MDGs may be used Examples
to provide drag for braking of ground vehicles (e.g., LDSB Low Density, Small Hemispherical
cars, trucks, buses, trains, etc.) and ships (e.g., Bumps
sailboats, motorboats, barges, transports, submarines, MDSB Medium Density, Small
etc.). The application of the device to tractor-trailers Hemispherical Bumps
would allow such vehicles the capability of improved HDSB High Density, Small Hemispherical
braking on ice or rain covered surfaces and since the Bumps
device can be applied to the trailer, the braking would LDLB Low Density, Large Hemispherical
not cause the vehicle to "jack-knife" as may occur Bumps
with conventional braking systems. MDLB Medium Density, Large
Hemispherical Bumps
This paper will discuss how MDGs work and HDLB High Density, Large Hemispherical
present data on drag increases found on wind-tunnel Bumps
models tested at NASA Langley Research Center test LDSP Low Density, Small Vertical Plates
facilities. MDSP Medium Density, Small Vertical
Plates
NOMENCLATURE HDSP High Density, Small Vertical
Plates
b wing span, inches LDLP Low Density, Large Vertical Plates
c chord, inches MDLP Medium Density, Large Vertical
Drag Plates
C drag coefficient,
D q S HDLP High Density, Large Vertical Plates
¥
Lift
C lift coefficient, DESCRIPTION OF WIND TUNNELS AND
L q S
¥ MODELS
C maximum value of C
L,max L
C rolling-moment coefficient, Wind Tunnel Facilitie s
l
Rolling moment
q¥ Sb A General Aviation (Whitcomb) number one
C yawing-moment coefficient, [GA(W)-1] wing model was tested in the NASA
n
Yawing moment Langley Research Center, 14- by 22-Foot Subsonic
q Sb Wind Tunnel which is a closed-circuit, single-return,
¥
D /D Ratio of the Drag of a Ridge System to Drag atmospheric wind tunnel with a test section that can
RS SR
of a Single Ridge be operated in a variety of configurations – closed,
h height of MDG, inches slotted, partially open, and open (Reference 2). The
L characteristic length (chord), inches closed section configuration is 14.5 ft high by 21.75
ft wide by 50 ft long with a maximum speed of about
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AIAA-98-2621
Research Tunnel (SBRT). SBRT is a low speed
facility with a 24- by 24-inch test section. The
tunnel operates at dynamic pressures, q , from 7 to 40
¥
psf. Figure 2 shows two of the test models installed
in the NASA LaRC SBRT facility.
b = 109"
c = 36"
Figure 1. GA(W)-1 model installed in the NASA Balance Housing
LaRC 14- by 22-Foot Subsonic tunnel.
c = 36"
Figure 3. GA(W)-1 airfoil and schematic of wing
planform.
Wind Tunnel Models
The present experimental investigations of the
MDG concept utilized hemispherical bumps and
vertical plates applied to a wing and a series of
representative fuselage shapes. However, the MDG
concept is applicable to rectangular, triangular, or any
other shape of protuberance.
The GA(W)-1 wind tunnel model is shown in
schematic form in figure 3. The wing had a 0(cid:176) -swept
planform incorporating a GA(W)-1 airfoil. The
GA(W)-1 is a general airfoil section developed to
provide performance increases over conventional
airfoils at subcritical conditions. The airfoil is 17
percent thick with a fairly blunt leading edge and a
cusped lower surface, trailing edge. The design C is
L
0.4 and the wing was designed to have good lift-to-
drag ratios at C of 1.0 (for climb); C occurs near
L L,max
a C of 2.0. In addition, the airfoil has a blunt
L
trailing edge with nearly equal upper and lower
Figure 2. Drag Body Configurations D1 (baseline) surface slopes to moderate the pressure recovery on
and D7.2 Installed in NASA LaRC the upper surface and postpone trailing edge
SBRT. separation and stall (References 3 and 4). The model
had a 109-inch span and a 36-inch chord. The center
338 ft/sec. The tests run on the GA(W)-1 model were panel had a balance housing, and forces/moments
conducted at dynamic pressures, q , of 45 and 60 psf were recorded using a 6-component strain gauge
¥
(0.17 to 0.20 Mach). Figure 1 shows the GA(W)-1 balance.
model installed in the 14- by 22-Foot test section.
Figures 4 and 5 show photographs of the
GA(W)-1 airfoil model with various MDG systems
In addition to the GA(W)-1 test, hemispherical-
installed on the surface. Figures 4a-c show the wing
capped, cylindrical drag bodies were tested in the
NASA Langley Research Center, Subsonic Basic
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Figure 4a. GA(W)-1 model with Large Vertical Figure 5a. GA(W)-1 model with Small Vertical
Plates and high density distribution Plates and high density distribution
(HDLP). (HDSP).
Figure 4b. GA(W)-1 model with Large Vertical Figure 5b. GA(W)-1 model with Large
Plates and medium density distribution Hemispherical Bumps and high density
(MDLP). distribution (HDLB).
Figure 4c. GA(W)-1 model with Large Vertical Figure 5c. GA(W)-1 model with Small
Plates and low density distribution Hemispherical Bumps and high density
(LDLP). distribution (HDSB).
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AIAA-98-2621
with high, medium, and low density, large vertical RESULTS AND DISCUSSION
plates (h=1/2 in.). Figures 5a-c show the wing with
the high density, small plates (1/4 in.), large Background
hemispherical bumps (1/2 in.), and small
hemispherical bumps (1/4 in.). The MDG concept takes advantage of flow
separation characteristics over surface protuberances
oriented approximately perpendicular to the local
flow direction. The MDGs would be deployed when
MICRO-DRAG GENERATOR/ required (through the surface of the vehicle; utilizing
DRAG STUDY BODIES
a variety of actuation concepts such as
microactuation, S hape M emory A lloy (SMA)
actuation or blown up [like a balloon], to extend the
required amount into the flowfield). It should be
D1: Baseline M noted that non-actuating “stall strips” have been used
on aircraft for many years to prematurely stall the
flow (to cause separation to occur in a more
predictable manner) usually on the upper surface of
the wing. Figure 7 illustrates the flow separation and
D2.2: Large Bumps, Low D
reattachment behind a hemispherical ridge and a
vertical plate or rectangular ridge. The flow
downstream of these shapes is very similar in size and
strength, thus producing similar drag increases and lift
D3.2: Large Bumps, High D
losses. Reference 5 describes the separation
characteristics of different shapes and how the
separation varies with boundary layer thickness;
references 6 through 10 describe how to estimate
D6.2: Large Plates, Low
excrescence drag due to various protuberances on
flight hardware.
2.4" 2"
Flow Over a Hemispherical Ridge
2" 1" 0.1"
14" 1"
D7.2: Large Plates, High
Figure 6. Hemispherical - Capped, Cylindrical
Drag Bodies.
It should be pointed out that the size of the
Flow Over a Vertical Plate
plates and bumps has been enlarged to match the size
of the boundary layers that would occur in the wind or Rectangular Ridge
tunnel. Flight hardware would require smaller
MDGs than the scaled-up versions of the wind-tunnel
models.
Twelve, 14-inch long Micro-Drag
Generator/dragb odies were fabricateda nd tested in the
NASA LaRC SBRT facility. Sketches of the Figure 7. Schematic of Flow Separation over a
baseline and four of the drag bodies tested in the hemispherical bump and a vertical plate.
SBRT facility are shown in figure 6. Variations in
MDG shape and spacing were investigated to Reference 11 describes how drag varies for
determine the “best” method of generating drag on an different profile shapes of ridges (i.e., non-actuating
aircraft fuselage or for application on a ground MDGs) placed on flat plates. The author also
vehicle. discusses how the height and width affect the drag of
an individual ridge as well as rules for spacing of
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AIAA-98-2621
ridges to optimize drag generation. These rules will Discussion of Wind-Tunnel Results
be discussed in the next few paragraphs.
In reference 5, it was determined from wind-
Flow Over a Series of Hemispherical Ridges tunnel tests that when properly spaced, the larger the
bump, the higher the drag. Thus, by properly
spacing the distance between MDGs of a given
h height, the flow separates downstream of the MDG
and reattaches just upstream of the next MDG. It
t
was found that the drag was greater for MDG shapes
s that had a flat face normal to the flowfield (i.e.,
plates) than for rounded shapes. The results obtained
Figure 8. Schematic of Flow Separation over on MDGs and for all the data presented in this paper
multiple MDGs. are for low speeds (M £ 0.20) and for low Reynolds
¥
numbers.
Table 1 describes the Configuration number,
MDG profile (e.g., low density small bumps-LDSB),
DRSDSR number of MDGs (N), and size as applied to the
GA(W)-1 wing. The table also points out which
configurations were asymmetric (MDGs applied only
to one side of the wing, i.e., the left-hand side
[LHS]).
Table 1: Description of MDG
Configurations tested on the
GA(W)-1 Model.
Figure 9. Variation in drag due to height of ridge and
Config. MDG Number Size, h
spacing between ridges for a zero pressure
Profile of (inches)
gradient.
MDGs
400 LDSB 6 0.25
Figure 8 illustrates the parameters available for
401 MDSB 12 0.25
producing optimum drag generation. When the
spacing between ridges is too large, the number of 402 HDSB 18 0.25
ridges, N, will be low and the resulting drag 403 LDLB 6 0.50
generation will be low. When the spacing between 404 MDLB 12 0.50
the ridges is too small, the drag will again be low, 405 HDLB 18 0.50
because the separation from the previous ridge will 406 LDSP 6 0.25
interfere with the downstream ridge effectiveness 407 MDSP 12 0.25
(burying the downstream ridge in the wake of the 408 HDSP 18 0.25
upstream ridge and thus, reducing the effective height
412 MDSB 12 (LHS) 0.25
of the downstream ridge). Figure 9 (from reference
413 MDLB 12 (LHS) 0.50
11) is a plot of the ratio of the drag of the total ridge
414 MDSP 12(LHS) 0.25
system to the drag of a single ridge (D /D ) versus
RS SR 415 LDLP 6 0.50
ridge spacing to height ratio (s/h). Plotted are curves
416 MDLP 12 0.50
of constant surface length to ridge height (L/h). The
plot indicates that a system of small ridges or MDGs 417 MDLP 12 (LHS) 0.50
can be more effective than one MDG. The optimum
drag generation potential is then a function of the Figure 10a illustrates how spacing affects the
shape, the size, and the spacing of the MDGs. Figure lift and drag characteristics of the GA(W)-1 wing
9 and references 5 through 11 were used extensively with 0.25-inch hemispherical drag bumps and figure
in the design of the wind-tunnel hardware. 10b compares spacing effects with 0.25-inch drag
plates. The MDGs were placed on both the upper
and lower surfaces of the wing in order to take
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maximum advantage of the surface area on which to configurations. By referring back to figure 9, an
increase the drag. optimum spacing may be achieved with fewer
MDGs; therefore, a minimum spacing between
Baseline, Conf. 2 MDGs may have been reached with a configuration
LDSB, Conf. 400 that falls between the medium density and high
MDSB, Conf. 401
0.80 density configurations. Due to system complexity
HDSB, Conf. 402
and weight, the medium density may provide the
optimum spacing and will be investigated further in
0.60
the following figures.
0.40
Baseline, Conf. 2
CL 0.80 LDSP, Conf. 406
MDSP, Conf. 407
0.20
HDSP, Conf. 408
0.60
0.00
0.40
-0.20 C
-4.0(cid:176) -2.0(cid:176) 0.0(cid:176) 2.0(cid:176) 4.0(cid:176) 6.0(cid:176) 8.0(cid:176) 10.0(cid:176) L
a 0.20
0.30
0.00
0.25
-0.20
-4.0(cid:176) -2.0(cid:176) 0.0(cid:176) 2.0(cid:176) 4.0(cid:176) 6.0(cid:176) 8.0(cid:176) 10.0(cid:176)
0.20 a
CD 0.15 0.30
0.10 0.25
0.05 0.20
0.00-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 CD 0.15
C
L
0.10
Figure 10a. Lift and drag characteristics of the
GA(W)-1 wing effect of small drag
0.05
bumps (M = 0.20).
¥
0.00
In figure 10a, the lift is reduced for any -0.2 0.0 0.2 0.4 0.6
C
application of MDGs on the surface. This occurs L
because most of the wing upper and lower surfaces Figure 10b. Lift and drag characteristics of the
have separated flow occurring on them. Even though GA(W)-1 wing effect of small drag
the wing appears thicker to the flow (because of the plates (M¥ = 0.20).
layer of separation on the upper and lower surfaces)
the flow is unable to expand to the same levels on Figure 11 shows the difference in drag
the upper surface leading edge (as was evident in generation between 0.25 inch and 0.50 inch plates and
surface pressure data, not included in this report). hemispherical bumps with medium density spacing.
Thus, the reduction in pressure difference between the Even though the drag is highest for the drag plates,
upper and lower surfaces reduces the lift. The drag drag levels on the rounded bumps is nearly as high
also increases for each of the MDG configurations and has characteristics that may be more appealing to
tested with the largest increase in drag occurring for military aircraft mission survivability and may be
the highest density system. However, the difference more easily applied by use of SMA technology.
in drag generation between the medium and the high
density distributions is not very great. Figure 10b Figure 12 shows the change in lift and drag
shows very similar results for the small plate (subtracting the baseline lift coefficient value at the
same angle of attack and baseline drag coefficient
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AIAA-98-2621
0.25 -0.050
MDSB, Conf. 401
Baseline, Conf. 2 MDLB, Conf. 404
0.20 MDSB, Conf. 412 -0.100 MDSP, Conf. 407
MDLB, Conf. 413
MDLP, Conf. 416
MDSP, Conf. 414
-0.150
0.15 MDLP, Conf. 417
D C
C L
D
-0.200
0.10
-0.250
0.05
* D C = C - C
L L,MDG L,baseline
-0.300
-4.0(cid:176) -2.0(cid:176) 0.0(cid:176) 2.0(cid:176) 4.0(cid:176) 6.0(cid:176) 8.0(cid:176) 10.0(cid:176)
0.00
-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 a
C
L
Figure 11. Drag characteristics of the GA(W)-1 0.200
MDSB, Conf. 401
wing effect of small drag plates (M =
¥ MDLB, Conf. 404
0.20, Medium Density spacing).
0.150 MDSP, Conf. 407
MDLP, Conf. 416
value at the same lift coefficient) and the percent
difference in drag for the four configurations plotted D CD 0.100
in figure 11. For all four configurations, the change
in lift is always negative and decreases linearly with
angle of attack and the change in drag is always 0.050
positive and increases with increasing lift. The
* D C = C - C
percent increase in drag due to MDG application D D,MDG D,baseline
0.000
clearly shows that the hemispherical bumps generate -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6
C
as much as 340% and 460% more drag than the L
baseline for the MDSB and MDLB configurations,
600%
respectively. The increase in drag for the plate MDGs
MDSB, Conf. 401
is as much as 460% and 570% for the MDSP and 500% MDLB, Conf. 404
MDLP configurations, respectively. Figure 12 MDSP, Conf. 407
clearly indicates that plates are more effective at 400% MDLP, Conf. 416
generating drag and reducing lift; however,
hemispherical MDGs also generate sizable changes in %DiffDrag 300%
lift and drag and may be more acceptable for certain
200%
applications and configurations.
100%
Since MDGs reduce the lift, deployment of * %Diff = {(C - C )/C } x 100%
Drag D,MDG D,baseline D,baseline
MDGs on one side of the aircraft (i.e., one wing or 0%-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6
one side of the fuselage) is expected to generate a CL
rolling moment. Since drag is also generated when
MDGs are deployed, an accompanying yawing- Figure 12. Change in lift and drag coefficient
moment coefficient would also be expected. The values as well as the percent difference
control effectiveness (capability to generate an in drag due to bumps or plates (M¥ =
asymmetric force or moment) resulting from 0.20).
deployment of MDGs on the left-hand side (LHS) of
the wing only is clearly shown in figure 13. As were generated (figure 13a). The changes in D Cn and
indicated in figure 13a, the baseline wing had non- D Cl (figure 13b) suggest the potential for MDGs as
zero yawing-moment coefficients (due primarily to control effectors. MDG control effectors could be
geometrical asymmetries in the balance housing at used to augment existing control surfaces (thus,
the centerline of the GAW-1 model shown in figure reducing the size and weight of existing devices) or
1). When MDGs were applied to the surface, used alone (eliminating existing devices). The plots
substantial moment coefficient values (C and C) also show that this type of control effector has
n l
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American Institute of Astronautics and Aeronautics
AIAA-98-2621
substantial control authority even at low lift with increasing dynamic pressure. Drag coefficient
conditions. Some control effectors generate large values varied from 0.3 to 0.4 on the baseline (D1)
0.000 0.000
MDSB (LHS), Conf. 412
-0.005 MDLB (LHS), Conf. 413
-0.005 MDSP (LHS), Conf. 414
-0.010 MDLP (LHS), Conf. 417
Cl -0.015 D Cl -0.010
-0.020 Baseline, Conf. 2
MDSB (LHS), Conf. 412 -0.015
MDLB (LHS), Conf. 413
-0.025 MDSP (LHS), Conf. 414 * D Cl = Cl,MDG - Cl,baseline
MDLP (LHS), Conf. 417
-0.020
-0.030 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6
-4.0(cid:176) -2.0(cid:176) 0.0(cid:176) 2.0(cid:176) 4.0(cid:176) 6.0(cid:176) 8.0(cid:176) 10.0(cid:176)
C
a L
0.000
MDSB (LHS), Conf. 412
0.005
Baseline, Conf. 2 -0.001 MDLB (LHS), Conf. 413
MDSB (LHS), Conf. 412 MDSP (LHS), Conf. 414
MDLB (LHS), Conf. 413
-0.002 MDLP (LHS), Conf. 417
MDSP (LHS), Conf. 414
0.000 MDLP (LHS), Conf. 417 D Cn -0.003
C
n -0.004
-0.005
-0.005
* D C = C - C
n n,MDG n,baseline
-0.006
-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6
C
-0.010 L
-4.0(cid:176) -2.0(cid:176) 0.0(cid:176) 2.0(cid:176) 4.0(cid:176) 6.0(cid:176) 8.0(cid:176) 10.0(cid:176) Figure 13b. The change in rolling- and yawing-
a
moment characteristics of the GA(W)-1
wing with MDGs installed on left-hand-
Figure 13a. The rolling- and yawing-moment
side (LHS) of wing (M = 0.20).
characteristics of the GA(W)-1 wing ¥
with MDGs installed on left-hand-side
D1: Baseline (No MDGs)
(LHS) of wing (M = 0.20).
¥ D7.2: Large Drag Plates, Dense Spacing
1.200
moments at low angles of attack and others at high
angles of attack; MDGs appear to generate substantial
1.000
moments across the angle of attack range (i.e., for all
lift conditions).
0.800
C
The second part of this experimental program D
was to explore MDGs for non-lifting surfaces such as 0.600
fuselages or ground vehicles. The next few figures
will discuss experimental results for MDG 0.400
applications on hemispherical-capped, cylindrical
bodies tested over a range of dynamic pressures at 0(cid:176) 0.200
5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0
angle of attack. q (psf)
¥
Figure 14. Drag Coefficient versus dynamic
Figure 14 presents the effect of dynamic pressure for the baseline drag body and
pressure on two of the cylindrical drag bodies (i.e., Configuration D7.2 (Large Plates, High
the baseline D1 and the HDLP D7.2 configuration). Density HDLP) drag body (a = 0.0(cid:176) )
These results indicate that the drag increment
resulting from MDG deployment on the D7.2 configuration and were approximately 1.0 to 1.05 for
configurations (see figure 6) remained nearly constant the large, densely-spaced drag plate (D7.2)
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