Concerning the flow about ring-shaped cowlings

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Material Information

Title:
Concerning the flow about ring-shaped cowlings
Series Title:
TM
Physical Description:
72 p. : ill ; 27 cm.
Language:
English
Creator:
Küchemann, Dietrich, 1911-1976
Weber, Johanna
United States -- National Advisory Committee for Aeronautics
Publisher:
NACA
Place of Publication:
Washington, D.C
Publication Date:

Subjects

Subjects / Keywords:
Aerodynamics   ( lcsh )
Radiators -- Thermodynamics   ( lcsh )
Genre:
federal government publication   ( marcgt )
bibliography   ( marcgt )
technical report   ( marcgt )
non-fiction   ( marcgt )

Notes

Abstract:
For application in practice for annular radiator fairings and similar arrangements, two new classes of circular cowls are developed by theoretical method, and investigated in a systematic test series regarding their behavior under various working conditions.
Bibliography:
Includes bibliographic references (p. 13).
Funding:
Sponsored by National Advisory Committee for Aeronautics
Statement of Responsibility:
by Dietrich Küchemann and Johanna Weber.
General Note:
"Report No. NACA TM 1360."
General Note:
"Report date October 1953."
General Note:
Über die Strömung an ringförmigen Verkleidungen. XII Mitteilung: Zwei neue Klassen von Ringhauben." Untersuchungen und Mitteilungen No. 3111. (ZWB)."

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 003769345
oclc - 85856732
sobekcm - AA00006169_00001
System ID:
AA00006169:00001

Full Text
c4p--







I


(7 34


NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS


TECHNICAL MEMORANDUM 1360


CONCERNING THE FLOW ABOUT RING-SRAPED COWLINGS

PART XII TWO NEW CLASSES OF CIRCULAR COWLS*

By Dietrich KUchemann and Johanna Weber


For application in practice for annular radiator fairings
and similar arrangements, two new classes of circular cowls
are developed by theoretical method, and investigated in a
systematic test series regarding their behavior under various
working conditions.


I. STATEMENT OF THE PROBLEM
II. DESCRIPTION OF THE CIRCULAR COWLS
1. The Two New Classes
2. Supplement to Class I of Cir
III. TEST PERFORMANCE
IV. RESULTS
1. The Two New Classes
2. Supplement to Class I of Cir
V. SUMMARY


cular Cowl


cular Cowl


SYMBOLS


x,r rectangular coordinates; x in direction of the axis of
rotation

RE radius of the cowl in the entrance cross section (narrowest
cross section in the inlet part)

Ra maximum outer radius of the cowl

RN radius of the hub in the entrance cross section


PN radius of curvature of the inlet lip

FE = IRE2 rRN2



Uber die Stromung an ringformigen Verkleidungen. XII Mitteilung:
Zwei neue Klassen von Ringhauben." Untersuchungen und Mitteilungen
No. 3111. (ZWB).


Abstract:


Outline:






NACA TM 1560


Fa = Ra2


FE/Fa


contraction of cowl


RE2
F 1/F =- R
E a R 2
a






vo







vE/Vo
Eomax/V



Vmax


contraction of circular cowl without hub



angle of attack


undisturbed free-stream velocity


mean value of velocity in the entrance cross section


inlet velocity ratio


inlet velocity ratio for a = 00 for same position of
the sliding throttle valve


maximum velocity on the outside of the circular cowl


local static pressure

static pressure in the undisturbed flow



dynamic pressure of approach flow, ~vo
o


local total pressure


Pges






NACA TM 1560


Pges Po
TE inlet efficiency; mean value of Pges P over the
entrance cross section* qo

E loss factor; mean value of Pges over the entrance
cross section* Po P


I. STATE 4MENP OF THE PROBLEM

The basic phenomena concerning the inlet problem in fairings of
propulsion units may be regarded today as clarified to a high degree.1
Still lacking is the systematic investigation of different forms for
the use in practice. On our part, there exist so far only two classes
of symmetrical circular cowls1 which are chiefly visualized for applica-
tion in inlets of special propulsion units. Due to their relatively
considerable contraction and their slenderness, they are, however, less
suitable for fairings of circular radiators or radial engines. It is
the aim of the present report to prepare usable cowls to include these
application purposes and to indicate their properties at least for the
incompressible case.

In the practical use of such cowls, it has always been found
expedient to indicate certain classes of cowls, the individual shapes
of which are related to each other so that an interpolation is directly
possible. This corresponds to a custom which proved very successful
also for standard wing profiles. Thus, we shall indicate, for the
application of circular cowls for radiator fairings, two new classes of
circular cowls in the form of geometrical systematics, and shall deter-
mine their properties for various flow quantities and angles of attack
with the aid of wall pressure-distribution measurements. Moreover, the
class I of cowls which has already been set up is to be supplemented by
further forms of particularly pronounced contraction.

*NACA reviewer's footnote: The symbols TIE and E are used in
figures 57 and 58 of the present paper and are not area weighted quanti-
ties as is indicated in the definition under the symbols. As used in
figure 57 TIE appears to be the arithmetic mean of the maximum and mini-
Pges Po0
mum value of As used in figure 58 tE appears to be one

minus the arithmetic mean of the maximum and minimum value of Ps
Po P

1Compare D. Kuchemann and J. Weber: Das Einlaufproblem bei
Triebwerksverkleidungen. Mitteilungen der Deutschen Akademie der
Luftfahrtforschung, 1943.






NACA TM 1360


II. DESCRIPTION OF THE CIRCULAR COWLS

1. The Two New Classes


Like the cowls previously set up, those of the two new classes
also have resulted from a theoretical calculation. Without discussing
in detail the actual calculation which is based on the method of
singularities, we shall describe here only the goal we aimed at.

The previous cowls of classes I and II had a relatively pronounced
contraction (FE/Fa 0.4) and were slender (the cylindrical piece on
which the maximum diameter was attained began at a distance 2Ra or
1Ra, respectively, from the entrance plane); the new cowls therefore
had to include the range of lesser contraction and, moreover, were to
be shorter. In the class III, the maximum diameter is attained at a
distance 1.Ra from the entrance plane and the values of FE/Fa are
between 0.3 and 0.5, whereas, the cowls of class IV are still shorter
(maximum diameter at 0.5Ra) and show still lesser contraction (FE/Fa
between 0.4 and 0.6). A further shortening and further lessening of
the contraction is hardly of interest for applications at present since
then the aerodynamic properties become too unfavorable as we shall see
below. Due to these slight contractions, it is not always possible to
round off the inlet lip to such a degree that even when nonmoving air
is sucked in (static conditions) no more flow losses in the interior
occur. However, this severe condition need no longer be set generally,
since we shall deal with engine or radiator cowls where such a state
of flow hardly occurs. Thus, the radius of curvature is considerably
smaller than would be required for the static condition; on the other
hand, it was, of course, kept as large as possible: for many applica-
tion purposes (for instance, drum radiator) a lip rounded as much as
possible, if only for reasons of space economy, is desirable; moreover,
the aerodynamic properties generally deteriorate considerably with
decreasing radius of curvature, also for high-speed flight and oblique
approach flow, as we shall see later.

As a measure for the aerodynamic load on the cowl, we had to
depend on the maximum excess velocity occurring, although at high speeds
it by no means necessarily characterizes the Mach sensitivity unequivo-
cally.2 Nevertheless, the value of vmax/v can convey a good com-
prehensive view of the behavior of the separate cowls and show, for
instance, the sensitiveness to variations of the working conditions,
and the possibility of an increase in drag by separation phenomena,

2Compare H. Ludwieg: Widerstandsmessungen an zwei Ringhauben bei
hohen Geschwindigkeiten. UM 3026, 1943.






NACA TM 1360


particularly in incompressible flow. In the calculation, which was
performed only for one state of operation, high-speed flight with
symmetrical approach flow, we endeavored to keep the value of vax/vo
constant in this state within one class of cowls. Thus, vmax/vo was
to be about 1.3 for class III for a vE/vo of about 0.3 (which generally
is approximately the case for radiator fairings), and about 1.4 for
class IV with the same flow quantity. As a consequence, the cowls with
lesser contraction also will have a smaller radius of curvature which
agrees with the geometrical facts.

The forms of the two new classes .of circular cowls are plotted in
figures 1 and 2, the coordinates are given in the numerical tables 1
and 2. Since it will almost always be necessary to interpolate a cowl
for a special purpose, diagrams which facilitate this interpolation
have been indicated in figures 3 and 4. The shapes of the insides of
the cowls have been shown in every case only up to the junction with
a cylindrical piece. At this point, one has to adjoin the inner con-
tour corresponding to the purpose; its shape may be assumed as highly
independent of the outer flow.


2. Supplement to Class I of Circular Cowls

Class I of circular cowls which is developed particularly for the
inlets of special propulsion units was indicated so far only up to a
FE/F = 0.25; however, since it frequently occurs that the cowl in
certain installation arrangements can be considerably more contracted
at least over part of the circumference, we supplemented class I in
this respect and indicated it up to values FE/Fa = 0.10. Shapes,
interpolation diagrams, and coordinates may be found in figures 5 and 6
and in numerical table 3.


III. TEST PERFORMANCE


We investigated three cowls of each of the two new classes: of
class III those with FE/Fa = 0.3, 0.4, 0.5, and of class IV those with
FE/Fa = 0.4, 0.5, 0.6 so that in every case the entire range is included.
In the model, all cowls had the same outer diameter 2Ra = 200 mm and
were continued cylindrically toward the rear corresponding to the sketch
in figure 7. By throttle valves at the rear portion cut-off at an
obtuse angle or, respectively, by a built-in blower, the flow quantity
which we indicate in the form of a ratio vE/vo was varied; in every
case, the wall pressure distribution on the cowl as well as the total






NACA TM 13.60


pressure and the static pressure in the inlet inside were measured.
The measuring plane was at a distance of 50 mm from the entrance plane;
the cross section showing the most extreme conditions in case of varia-
tion of the angle of attack was singled out; measurement of the entire
circular cross section was omitted.

For the following results, the wall pressure distributions have
been indicated in every case for the various inlet velocity ratios
for a = 00 and for vE/vo = 0 and also for various angles of attack,
since for this state the most extreme values occur. For the other
inlet velocity ratios too, series of angles of attack have been measured
but not indicated in detail. The results, if desired, may be had from
the AVA. We merely determined and plotted the occurring maximum excess
velocities.

The flow quantity was determined from the measurement in the inner
cross section and, due to the simplification in the measurement, is
correct only for the case a = 00. We kept the throttling position
constant for angles of attack different from zero and indicated, for
characterization of the flow quantity, the corresponding value for
a = 00 which is denoted by VEo/Vo.

Furthermore, we should like to point out a certain dubiousness in
the measurements with angle of attack which is caused by the body shape
used behind the inlet cowl (compare fig. 7). Since, in case of oblique
position, the entire body is subject to a lateral flow which is the
reason for the dissymmetry on the cowl, and since this lateral flow in
turn depends partly on the body shape, the variation of the excess
velocity with a also will be influenced by the body shape, for this
reason. It would therefore be more accurate to introduce also for
these measurements a number corresponding to the lift curve slope for
standard win. profiles, and thus to correct the results. Anyway, the
results can give a good comprehensive view in the form indicated. We
evaluated the measurement in the inner cross section also as to the
losses occurring in the inflow; we indicated it in the form of an
inlet efficiency


Pges Po





Especially for the static condition, where this definition fails, we
used a loss factor

p p
E = ges
oE p
PO P






NACA TM 1360


which sets up a relation between the actual kinetic energy of the flow
and the energy to be expected theoretically. For both quantities, the
mean values have to be taken over the entrance cross section.

For the circular cowls investigated, one may assume that they
frequently are used in combination with a projecting hub. Thus, we
investigated all cowls also with hub. In order not to increase the
number of parameters prohibitively, we used only similar hub shapes
which all obstruct exactly half the entrance cross section of the cowl
and one developed as ellipsoids of revolution of the axis ratio 2:1
the small axis of which lies in the entrance plane of the cowl. In
proportion with the outer diameter of-the cowl, the hubs are thus
different for the different contractions of the cowls (compare figs. 8
and 9).

The tests were carried out in the wind tunnel of the KWJ (0.7 X 1 m
free jet).


IV RESULTS

1. The Two New Classes


The measured results obtained on the classes III and IV of circular
cowls are given in figures 10 to 46. The cowls with the largest con-
traction of each class have a pressure distribution with a flat minimum
lying relatively far to the rear. Due to the pronounced rounding of
their lips, these cowls are rather insensitive to variations in flow
quantity as well as in angle of attack. The presence of a hub on
which there appears, particularly for small flow quantities, the known
boundary-layer separation also produces only a very slight drop in
the excess velocities.

With decreasing contraction, the excess velocities do not rise at
first, in contrast to the experience with cowl class I. The reason
lies in the simultaneously reduced rounding of the lip whereby the
pressure distribution flattens noticeably without the minimum assuming
a lower position. These phenomena can be observed in the models of
even the least contracted cowls of both classes which becomes particu-
larly clear in the comparative plots of figures 47 to 56. It is true
that these cowls, especially those of class III with FE/Fa = 0.5,
then are extremely sensitive to every change in working conditions. In
the wall pressure distributions, one can find, even for a = 00 and
small flow quantity, at least local separation phenomena with a very
steep rise of the excess velocities; the same occurs in case of small
variations in angle of attack. Although these processes need not






8 NACA TM 1360


absolutely make themselves felt in an increase in drag, -such an increase,
to a considerable degree, is to be expected for the separation phenomena
which are clearly recognizable in the figures. In the plotting of vmax/vo
the regions with local separations have been drawn in dashed lines, those
with complete separation in dotted lines.

Since the cowls with slight contraction possess a very pronounced
narrow pressure minimum directly at the inlet lip, this pressure minimum
can be noticeably influenced by the welling over of the flow made tur-
bulent by the hub separation. An already existing local separation in
the case without hub thus frequently may be made to disappear completely;
the drop in excess velocities also may be considerable.

Entrance losses generally do not occur in case of the cowl without
hub. Only for very large angles-of-attack do separation phenomena
appear on the inside of the less rounded cowls. Of importance though
is the loss factor for static condition which rises continuously with
decreasing radius of the lip. The development of a region of separa-
tion in the interior space for static condition is, naturally, notice-
ably impeded by a hub. In high-speed flight, however, the projecting
hub may cause considerable flow losses, the effect of which can be very
noticeable for instance on the radiator lying behind the hub.

On the whole, we can state that the theory has yielded a number of
usable circular cowls, and that the theoretical predictions have been
satisfactorily fulfilled. It is now possible for the designer to
select without delay a cowl useful for his purposes, the properties of
which are known to a great extent. For the application in annular
radiators and radial engines, generally, a cowl of class IV will best
meet the requirements under present standard conditions. In a later
report, we shall discuss what conclusions may be drawn from the existing
measurements quite generally for the design of annular radiators.


2. Supplement to Class I of Circular Cowls

In the newly added cowls of class I, the very pronounced rounding
of the lip is particularly striking; at first glance, it appears almost
clumsy. This is, however, to a great extent, a corrigible matter of
habit since the aerodynamic properties of these cowls must be denoted
as very favorable. A pressure distribution measurement on a nonrota-
tionally symmetrical cowl (this is the application they are predominantly
meant for) may serve as evidence. The cowl measured was of circular
cross section in its lower part (class I with FE/Fa = 0.3) and in the
upper part continuously thickened up to the ridge where it attains a
(local) FE/Fa of 0.1. The wall pressure distributions in the state
of most extreme stress (vE = 0) for various oblique approach flows show






NACA TM 1360


a favorable course so that such an inlet form seems suitable, especially
for the wing installation of special propulsion units. The related
problems will be discussed in detail in a later report.


V. SUMMARY


Two new classes of circular cowls are indicated for use in practice
which are particularly suitable as fairings of annular radiators and
radial engines. For any existing purpose, a cowl may be interpolated
from completed diagrams in the simplest manner; the aerodynamic pro-
perties of each cowl may be largely ascertained from a systematic test
series. Thus, the maximum excess velocities on the outside of the cowl
and the certain losses for the various inlet velocity ratios and angles
of attack are given. Furthermore, the states for which separation
phenomena occur can be recognized.

The already existing class I of cowls is supplemented by cowls of
particularly strong contraction as are needed in some cases for installa-
tion in special propulsion units.


Translated by Mary L. Mahler
National Advisory
Committee for Aeronautics






NACA TM 1360


NUMERICAL TABLE 1

CLASS III OF CIRCULAR COWLS


0.35

r/RE


r/RE


0.45

r/RE


0.5

r/RE


Coordinates of the outsides


1.190
1.351
1.420
1.473
1.515
1.550
1.580
1.628
1.665
1.695
1.720
1.741
1.759
1.774
1.786
1.797
1.806
1.813
1.818
1.822
1.825
1.826
1.826
1.826


1.136
1.267
1.327
1.373
1.410
1.441
1.468
1.512
1.547
1.575
1.598
1.618
1.635
1.649
1.660
1.669
1.677
1.683
1.687
1.689
1.690
1.690
1.690
1.690


1.091
1.203
1.255
1.295
1.328
1.356
1.381
1.421
1.453
1.479
1.501
1.519
1.535
1.548
1.558
1.566
1.572
1.577
1.580
1.581
1.581
1.581
1.581
1.581


1.056
1.155
1.201
1.236
1.265
1.290
1.313
1.350
1.379
1.403
1.423
1.439
1.453
1.465
1.475
1.482
1.487
1.490
1.491
1.491
1.491
1.491
1.491
1.491


1.030
1.116
1.156
1.187
1.213
1.235
1.255
1.288
1.315
1.337
1.355
1.370
1.382
1.393
1.402
1.408
1.412
1.414
1.414
1.414
1.414
1.414
1.414
1.414


Coordinates of the insides


1.067
1.031
1.010
1.001
1.000


1.032
1.008
1.000
1.000
1.000


1.011
1.000
1.000
1.000
1.000


Radius of curvature
PN/RE


(Coordinates of the center of
curvature: x = PN; r = r
for x = 0)


0.132 0.090


FE/Fa

x/RE


= 0.3

r/RE


.05
.1
.15
.2
.25
.3
.4
.5
.6
.7
.8
.9
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0


0.05
.1
.15
.2
.25


1.001
1.000
1.000
1.000
1.000


1.000
1.000
1.000
1.000
1.000


PN/RE = 0.180


0.056 0.030






NACA TM 1360


NUMERICAL TABLE 2

CLASS IV OF CIRCULAR COWLS


FE/Fa

x/RE


= 0.4

r/RE


0.45

r/RE


0.5

r/RE


0.55

r/RE


Coordinates of the outsides


0
.05
.1
.15
.2
.25
.3
.35
.4
.45
.5
.55
.6
.65
.7
.75
.8
.85
.9
.95
1.0


1.130
1.290
1.354
1.400
1.437
1.467
1.492
1.513
1.530
1.544
1.555
1.564
1.570
1.575
1.578
1.580
1.581
1.581
1.581
1.581
1.581


1.105
1.245
1.301
1.341
1.372
1.397
1.418
1.436
1.451
1.463
1.473
1.480
1.485
1.488
1.490
1.491
1.491
1.491
1.491
1.491
1.491


1.083
1.203
1.251
1.286
1.313
1.335
1.353
1.369
1.382
1.392
1.400
1.406
1.410
1.412
1.414
1.414
1.414
1.414
1.414
1.414
1.414


1.063
1.164
1.206
1.237
1.261
1.280
1.296
1.310
1.321
1.330
1.337
1.342
1.345
1.347
1.348
1.348
1.348
1.348
1.348
1.348
1.348


Radius of curvature
PN/RE


PN/RE = 0.125


(Coordinates of the center of
curvature.: x = pN; r = r
for x = 0)


0.100 0.078


0.6

r/RE


1.045
1.127
1.165
1.193
1.215
1.232
1.246
1.258
1.268
1.276
1.282
1.287
1.290
1.291
1.291
1.291
1.291
1.291
1.291
1.291
1.291


0.058 0.040






NACA TM 1360


NUMERICAL TABLE 3

CLASS I OF CIRCULAR COWLS


0.15

r/RE


0.2

r/RE


0.25

r/RE


0.3

r/RE


0.35

r/RE


0.4

r/RE


Coordinates of the outsides


1.241
1.369
1.443
1.558
1.645
1.718
1.781
1.836
1.885
1.930
1.971
2.010
2.080
2.143
2.200
2.250
2.293
2.331
2.366
2.397
2.425
2.450
2.473
2.493
2.510
2.526
2.540


1.195
1.322
1.386
1.478
1.547
1.604
1.653
1.696
1.735
1.771
1.804
1.834
1.890
1.940
1.983
2.021
2.054
2.082
2.107
2.130
2.150
2.167
2.181
2.194
2.206
2.216
2.224


1.-170
1.291
1.345
1.417
1.473
1.518
1.557
1.592
1.623
1.652
1.679
1.704
1.750
1.790
1.825
1.855
1.881
1.904
1.925
1.943
1.958
1.970
1.980
1.988
1.994
1.998
2.000


1.163
1.265
1.310
1.371
1.418
1.457
1.491
1.521
1.548
1.573
1.596
1.616
1.651
1.681
1.707
1.730
1.750
1.768
1.783
1.796
1.806
1.814
1.820
1.824
1.826
1.826


1.158
1.247
1.284
1.334
1.374
1.407
1.435
1.460
1.483
1.503
1.521
1.537
1.564
1.587
1.607
1.624
1.639
1.652
1.663
1.672
1.679
1.684
1.688
1.690
1.690


1.155
1.239
1.269
1.309
1.342
1.369
1.392
1.413
1.432
1.449
1.464
1.477
1.499
1.517
1.532
1.544
1.554
1.562
1.569
1.574
1.578
1.580
1.581
1.581


FE/Fa

x/RE


= 0.1

r/RE


0
.05
.1
.2
.3
.4
.5
.6
.7
.8
.9
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
4.0


1.312
1.442
1.528
1.660
1.769
1.861
1.941
2.011
2.074
2.132
2.186
2.238
2.332
2.415
2.489
2.557
2.619
2.676
2.728
2.775
2.818
2.857
2.893
2.926
2.957
2.985
3.010






NACA TM 1360


NUMERICAL TABLE 3 Concluded

CLASS I OF CIRCULAR COWLS


FE/Fa =

x/RE

4.2
4.4
4.6
4.8
5.0
5.2
5.4
5.6
5.8
6.0
6.2
6.4


0.1

r/RE

3.033
3.055
3.075
3.092
3.107
3.120
3.132
3.142
3.150
3.156
3.160
3.162


0.15

r/RE

2.552
2.562
2.570
2.576
2.580
2.582


0.2

2r/RE

2.230
2.234
2.236


0.25

r/RE


0.3

r/RE


Coordinates of the insides


0.05
.10
.15
.20
.30


1.063
1.032
1.015
1.006
1.000


1.063
1.032
1.015
1.006
1.000


1.063
1.032
1.015
1.006
1.000


1.063
1.032
1.015
1.006
1.000


1.063
1.032
1.015
1.006
1.000


Radius of curvature
PN/RE


(Coordinates
x = PN; r


of the center of
= r for x = 0)


curvature:


0.180 0.157 0.135 0.115 0.110 0.090


0.35

r/RE


0.4

r/RE


1.063
1.032
1.015
1.006
1.000


1.063
1.032
1.015
1.006
1.000


PN/RE = 0.205





NACA TM 1560


FE FO


Figure 1.- Class III of circular cowls.


r/R E

t





NACA TM 1360


Figure 2.- Class IV of circular cowls.


FE/Fo
0.40
0.45
0.50
0.55
0.60


r/RE

t





EACA TM 1560


SI N I
.- oIdddo


- 0
o
oo


// ll 1





L











l--


X/1 V









OD ,z//,


cr -
a-'




NACA TM 1560


odd


,'


In
-o
8 0
0


fI


0


I


0
1o


I11 /








Ln
0

I!'7 1 1
I/i!
(tiil

;/11!
hll l
g.1711 !/


w
No


-







NACA TM 1360


l -i C- o-

LL








































----- ----
-ii:




















ol








z///// /

















__ // 3 /i I





__/||'///'1/i!I 44 I_
,iil/,///!/ / it/,rIIrI,


NACA TM 1560


LLU
t


0
U
k
O
o
o


o
1-4




m
nl
--4
U'
*-4



-I
03


M
,-I


0. Q! WC Cli 0
w J e CJ
w
LlJ
\t-


Z c. 7





20 NACA TM 1560






--4






K .)



o
0






S/D

.4
')
\ \I (U
6c






NACA TM 1560 21









/O______ __ F=0.3
oo -















SF/F 0,4
SEOE


FE/F= 0.5


Figure 8.- Class III of circular cowls.





NACA IM 1360


FE/F =0.6






FE /1=06


Figure 9.- Class IV of circular cowls.








NACA TM 1560


25





















0
0
o
o



II
1r1





*d






0






I1






0
'-4
o




Cd
r-4
0

0r
I-
I-

O-

M]
MS~







NACA TM 1560


0




0
-----M\-------


















O






0
















00 a






0 00





-O c
-- e -- o "n lv
. o






"I o o o


n


Cd














o
0





[9








cd
-4
U
I






NACA TM 1360


OD






x'


























a









0. 5/






OO
0-






NACA nl 1560


VE/Vo


Figure 13.- Class III of circular cowls; FE/Fa = 0.3.


v
Vmox
V
0
4






NACA TM 1360


VE IVO
1.7 0
Without hub
0.2
vmax
max 1.6 I04 -


T / 0 1.o.
00.8

1.5 _00 .


r ---- .....-o



1.3______ ___ _________
,. -- t7
With hub
^ 7^ ^ --- --- --- --- --- --- -t6- -- -- -- --




1.1 -





10 0 ,


1-52-







-5 0 5 10 15


Figure 14.- Class III of circular cowls; FE/Fa = 0.3.








NACA TM 1360


-00
CO
J: Ic







NACA TM 1560


P- PO
qo

0.5

a= x /Ra -

12 012 0.3 0.4 0.5 0.6 07 0





a: _- -------- --/R



00 .
go-


-05











/ ++15/
+








-2.5




-30




-3.5


Figure 16.- Class III of circular cowls (without hub); FE/Fa = 0.4,
vE/vo = 0.












-I T-I 1-


-- -- --


o- 11











O 11



0
---- -----









-7
1o




to __n o



II I 1t
EEEE^ III/lEEtEEE

<' 1 11{t l\' ,
"" I r ^ T1^ '0"" -


0. f-
,< <>
c,1<


NACA TM 1560


II






-4

~W
o i
0
O

go
"-4
o



0
I--I

C--
I-
T-t



Vr
tQr


I I







NACA TM 1560


0.2
0
o.4
o0.6


I /


ap I


Figure 18.- Class III of circular cowls; FE/Fa = 0.4; vEo/Vo = 0.






NACA TM 1360


Figure 19.- Class III of circular cowls; FE/Fa = 0.5, a = 00.







NACA TM 1560 55


1.0____--



Q5
05


qo \a I,-
i 0 0.1 -15 0.2 0.3 0.4 0.5 0.6 07 0.8














=ao4_ --- ------- --
-9-












-1.5




-2.0-


Figure 20.- Class III of circular cowls (without hub); FE/Fa = 0.5,
vE/vo = 0.







54 NACA TM 1360O





















0 0"-i0
CC






C0
-- .-
tr'O






0U
o o


O oo I"





co


S\






rjZ-^ } T


nOiSlrt
cr






NACA TM 1560 55


Figure 22.- Class III of circular cowls; FE/Fa = 0.5.






NACA TM 1560


o-1.U.
0- -





Without hub
-I
0.t 0.2 0.3 04 0.5 06 07 0_
P-Po \



-- ----Outside





VE/Vo=O 0.19 0.45 0.67
-1.0


P-Po
qo
SWith hub

\ 0.2 0.3 0.4 0.5 0.6 0.7 0(

a-

-0.5






VE/Vo=0 0.42 0.70 .23
1111O


Figure 23.- Class IV of circular cowls; FE/Fa = 0.4, a = 00.






NACA TM 1_0U


I_ to


0.1 0.2 0.3 0.4 0.5 06 0.7 0.6

.P-p_ ___ ___ ___



00







+60



-2 .0._ __
--T--





Figure 24.- Class IV of circular cowls (without hub); FE/Fa = 0.4,
VE/Vo = 0.


I I 1 I r 1 I I I I






NACA TM 1560


1A1 1
*11..--


i d \\ \\\\






IIII-^


0 / -- ,- -
_^ SY'#n/P.I ^ ^YC+
lc


- 0
-- X



0
II
44

C)








-4

0
cQ



SO
!o



*J
la)


cl-P-
I C FO
Cx






NACA TM 1560


Vmox
Vo
0t


I"1 liAX


'~J~i71>


VE/VO=


iir


Without hub

1.7

1.2 Vmax
Vo VEo/Vo
1-..6 0__
.--- 0.2
1.1 -t7 "- 0.8

.1.0

5.4.
.0 0..


- 0 55 1 15a
0,Vo. o 1 With hub




1.20


0.1


-5 0 5 100 150


Figure 26.- Class IV of circular cowls; FE/Fa = 0.4.


J







NACA TM 1360


Figure 27.- Class IV of circular cowls; FE/Fa = 0.5, a = 0o.


P-Po
qo






















P-Po
qo






NACA TM 1360


P- Po
q -- x R -
0.1 0.2 0.3 0.4 0.5 06 .7
a=
-150


















-2.0 +9. -
-120





















-2.5




-3.0 -



Figure 28.- Class IV of circular cowls (without hub); FE/Fa = 0.5,
VE/Vo = 0.
vE/vo = 0-






NACA TM 1560


P- P
0
Pstv
o.5

x/RC -
S0.1 02 3 0.4 0.5 0.6 0





?^-=-- -- -- -- -- -- -- .----








-+9 +120 +150

-2.0

Figure 29.- Class IV of circular cowls (with hub); FE'/Fa = 0.5,
vE/Vo = 0.







NACA TM 1560


"" a


Figure 30.- Class IV of circular cowls; FE/Fa = 0.5.







NACA TM 1560


1.0




0 ^- __ ----- ----




S0.1 0.2 03 04 0.5 0.6 0.7 08
P-P
- go x/Ro




--*-- Without hub



VE/VO=o 0.14 0.31 0.45



-1.5 Outside




-1.0p 2.0 --


P-
qo -2.5
E -2.5



S0.1 0.2 0.3 04 0.5 0.6 0.7 0




-05 "_ With hub



E/Vo= O 0.45 0.62 0.98




Figure 31.- Class IV of circular cowls; FE/Fa = 0.6, a = 00.






NACA TM 1560


i.0



P-P
0 ----
4o




0.1 0.2 0.3 04 0.5 0.6 / 0.7





-E.5




.+90.0 .+120 15











-2.0




-2.5




-3.0




-3.5


Figure 32.- Class IV of circular cowls (without hub); FE/Fa = 0.6,
vE/vo = 0.






NACA TM 1560


Figure. 33.- Class IV of circular cowls (with hub); FE'/Fa = 0.6,
VE/Vo = 0.


P-Po
f
f






NACA TM 1360


Wa


Figure 34.- Class IV of circular cowls; FE/Fa = 0.6.





NACA TM 1360


Pges- o-
0 0.2 qo 0.6 08 1.0
\N N I VE/YO



0.29


x 0.61
p\ p
\\ \^ \ ^to.6








\ IN





o =2 __
--- Static condition---
0 0.2 0.4 0.6 0.8 1.(


-4- Pges- PE
-- ^ P _


)


Figure 35.- Class III of circular cowls (without hub); FE/Fa = 0.3.


-t--il iIirI ll iI


U






NACA TM 1560


Figure 36.- Class III of circular cowls (with hub); FE'/Fa = 0.3.







NACA TM 1360


I *
n1 1~S-19 gs04


QB


-
LO


-4 4


r/F


Q6 1 N \ \



0.4\ \



0-




S.4
\ \0.46

























$ a= 00
0 = 60



Static condition





Po-PE
Figure 37.- of circular cowls (without hub); F/F 0.4.









Figure 37.- Class III of circular cowls (without hub); FE/Fa = 0.4.






NACA TM 1360 51


Figure 38.- Class III of circular cowls (with hub); FE /Fa = 0.4.






NACA TM 156o


0 0.2 0.4 0.6 0.8 1t

Figure 39.- Class III of circular cowls (without hub); FE /Fa = 0.5.






NACA TM 1360


Figure 40.- Class III of circular cowls (with hub); FE'/Fa = 0.5.





NACA TM 1360


Pges-Po
0.2 0.4 0.6 0.8 1.
\ \ V\ E/ iV

0.4
r/Ra ___

o\\\ \ \ \ 29



\ E Stati-iontii
0, 2


\ \- \ \ I-







\ \ \-\ -






0 0.2 04 0.6 0.8 t0
^X-__-v- -~-^---^







Figure 41.- Class PV of circular cowls (without hub); FE/Fa = 0.4.






NACA TM 1560


Figure 42.- Class IV of circular cowls (with hub); FE'/Fa = 0.4.






NACA TM 1560


'4'l


04


0.2


C


g--es- -
0 Q2 O O.S ~ 08 1.0
S\ V/V Without hub



\ \\\",\_
\" \ \ \ \ \\ i^ o
\0 7 ____




S3 -_ 39


-.55






















0 0.2 04 (PesPE)/(PO -E)

Figure 43.- Class IV of circular cowls; FE/F = 0.5.
Fig-ure 43.- Class IV of circular cowls; FE/FaB = 0.5.






NACA TM 1560


Figure 44.- Class IV of circular cowls (with hub); FE'/Fa = 0.5.






58 NACA TM 1360


0 -- 02 q 0.4 0.6-- 0.8 -- .0---
07 1o
0.2- -


0.4



-o \ 12.
0 \\ \0 \ \ \ c d 14 oi











x, j
\ \ \ \ f
















x = 60
1 \ 20



"Static condition
_-4


U U.2


W4 (Pges-E)/(Po-E) "


Figure 45.- Class IV of circular cowls (without hub); FE/Fa = 0.6.


1/1






NACA TM 1360 59


Figure 46.- Class IV of circular cowls (with hub); FE'/Fa = 0.6.






NACA TM 1560


-- X/R
0 0.1 Q2 03 0.4 0.5 0.6 07 0. 0.9



0.9




FE /Fa -

0.7 0,5 _

0.4
6.3 -
O--* 0.3

--__ x/Ra

0.1 0.2 0.3 0.4 05 0.6 0.7 0.8 OS










S = 0.4

.5 1o = 0.5
-1.5


Figure 47.- Class III of circular cowls (without hub); VE/Vo = 0, c, = 0o.


r/RC

It


p-p



t





NACA TM 1560


P- Po
90
a


Figure 48.- Class III of circular cowls (with hub); VE/vo = 0, a = 00.






NACA TM 1360


---W- x -- -

10 O.1 0.2 0 0.4 0.5 06 0.7 OB O.S








o FE-/

0.7 -1 0.5

0.4


S 0.3



0.5



1 01 2 0.53 0.4 0.5 Q6 0.7 0.8 0




-0.5


FE/Fa = 0.3
-1.0 -- = 0.4
0 = 05


Figure 49.- Class III of circular cowls (without hub); vE/vo = 0.3, a = 00.


r/Ro

t


P- Po
qo







NACA TM 1560


P-P0


f-05


Figure 50.- Class III of circular cowls (with hub); vE/vo = 0.3, a = 0.






NACA TM 1360


Figure 51.- Class IV of circular cowls (without hub); VE/Vo = 0, a = 00.






NACA TM 1560


Figure 52.- Class IV of circular cowls (with hub); VE/Vo = 0, a = 0.







NACA TM 1560


Q0 0.2 0.3 0.4 0.5 0.6 07 0.8

r/R-0


So.8




0.6


0.7 0.2

----0.4
Fu 3----- o.4
0.6


0.5

P Po --V x/Ro
o
O 0 0.2 03 04 05 0.6 0.7 08




-Q5




.0------ =0.5 -
I o = 0.6

Figure 53.- Class IV of circular cowls (without hub); vE/vo = 0.3, a = 00.





NACA TM 1360


1.0

r/Ro

0.9





0.7


0.6



P- PO
qo





-0.



-1.0


Figure 54.- Class IV of circular cowls (with hub); vE/vo = 0.3, a = 0.


-, x /R
-- ---- -- 1^ 1x/.o -

01 0.2 0.3 04 0.5 0.6 0.7 0.
-- -- .^ -- -- -- ..----- -- -





E- __ -
0.6

0.5


0.4



5

--,. x/Ra
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8




\\-^-----------


SO F' = 0.4
--.---- = 0.5
0 = 0.6
-I-I-








WACA Til 1560


d o d d d oo o _
0--- -










0 I I'--- M\
t






S-



































>00\C V() fl
>n 0l r c
-- -- -- -- -


X
E>o-


0
II
o

a


cr,
4-J



C?
o






c)
0


5-3


*l-


I


ll -






IIACA TM I15t


0-
**N


Co'ioo
JI/ /IV/


177VA' I N


S--o








i,,ir


I'

w


x
iip~4~
F3
E


\ I"i


d








u-0



ILC


*


.0
U
0
?-1




0
a,
Co

ni

hDf




0')






IJACA TM 1560


Figure 57.- Inlet efficiencies.


QE

t.6


0.2 0.4 0.6 0.8 D 1.2 1.4
VE/Vo



















































Figure 58.- Internal losses for static condition.


NACA TM 1360


0.14 0.16
---P/RE






NACA TM 1360


Wall pressure distribution on
ridge section; v= O


Figure 59


NACA-angley 10-22-53 1000


P-Po
qo

0.5


-0.5







- 0 z gS
aj -O o m a n^ r ) co CI a nh"_

u S
L. o- o- s :"^in -~ I;ao"a*^

a- -0 c ,

~ ~ *! *i4 c-r-13 <^ s-^
in .^ L. u^E^~ in .* 'CIg.| g~
W W V 3 -4~ .

03 5 cc aB ci a



B ~*P la ^ S
oL DCSU S w a,'S
o o ^g I4 -5 g\
P4 ) i
u n I.IL i





pi m Ni tti cigM 2 s' at B a> U .f- 03. --JSB W ..g3" S



jo iE 0 l
Ji. I.s d |0- V' "V
o~ot





llt b lll
V 4):




Z l u = 2 P Ej t-
s ar
er0 -a I. e in



94 a .4 i$4 5 L 11
.250 c .2


"^| 0, w E- H gla |
=~) r- 0o oJ 1 14 Z
I..



up 0> 0 >W g W ,,<
-1 V3 *W z
*0 U C0



s~isstii1 l1s5 ti s!||atcjl | |i;

cc0 V bb co 0 Z 0 Us

^^~~ ~ ", -'' el S" |
c1 B to g ca 4) .- V
k s j E-4 l a .5s=iw t i
0a- bd 0
L ;4v g I U
OLI~C. 0 VP~04 0 V



.2 va C t:o
.01J--M s.g s .
0 0 V 0 k W L
~~a~l (u 4 ) P4 w a
r. Z U o M I0


a, a' C4 U
Z C: c Z Z
u w ~ ~ 0rn-i --







.[ -4 4U V %U... 0 &4.Z Z ) g
ct Z~V ~ t O





1.0 Ig s I g I









"~~~ ~ ~ U 40Q ^*i.*( i i S- Q'00K_ (u^ Lcj I
Ga4 v.4 V

,i di ene


- S. .. g W- _
C;i3 *-- bDO .in c.0









Cg r.- 1 g od Ei V
C|s vf I &. 1 14 2 I1















0"' 52 w .~ 0K *aB' 1. g 0 -4i -3S. 2 *1 3
Ciggi^i V.11 1. ^iyg"j ii| ^
C88g~Bt j
ciWA, --. Rq ft 'r. Z c





GJ Q 0 1. C: o



oI 4)0 t
0.(W *-a C C w 0 ZP
4 P






03 ~ ~ 0 >V CZV L)M Z UC CC4UM
-N 0








1.503 Ib.nM IIz .2 oo
0~~~~ ~ ~ .- 'ZM=- T V b
ZI t p 106I
W cx" Z6 9.5 6 b
QaI1




21 a u 0 U :0



edI L. 4 : pL
>z C.ZC V 0 z *2rn

00 5 Go < wn Z-C 0-

C Id ZZUUU *
z zu u cd 'E.4 LN E UO u 11




I






63 -^ -^a "" "

oca s.
43 M- O. t -.6"3[o< B lg~ 0I.; 43 tn-ii "3
5.. 0 -o---; a 0 a' I'. 15 0o-o ? So*f 4S3 1
. z M IN Z Z i
8 1. M



E Alu sill i 4) C !
m k 0 CJc

- 4 43 o I52, 4 t.B
-43.




_) c 44 Mr-
0 0
4h 3 r *S B a 'S 4B
Co ;a U M 0 h a-a 0, -

a I .cu "' a'' ^ B 1, C 3 |p Iw =5
;I II: II 1 A
Z U 0 0






I I-

-C !ji:,24
a 3-. i3 To g 00F. 4.mq o1
'200 0> 0.noi43c u
W*.~-, O.. 4. 0 -0~ 0c F
'r 00 ..43- 0t1
5 a,*g W a)~~0 5.0 0

u~~i-.; -.g3. w s.
vs- 04 .. 9: 2 C


0 woaP

z~3 U0 .
be wC: z '0* D 00 Z 00ok F


43- -. |I


Z Z 00 5 "Mgl



* 43 ,- 0









L 0 i b 0 ,..
<.0
V 0





0 g Ei ca
C I -.'! b





m w .. U .% A


-5 C? r- ;5S 4) :5
oo









-psg4 g~j 0
0 (D ~ 4)




^l.lslJ HaiS- j
o~ 6





E 0o &
0~ ~ ~ o Vca

EL. O ,6 4 ULV..9
'o. 0>4>
0, w 'c~ 0 Z. 043
< blm L 80

060
ZU.2 z u 1 ~. 3: 0 .k L
;9 0 m









I







UNIVERSITY OF FLORIDA
I III IIIIIIIIH80 I2 6lI1
3 1262 08105 825 6