AD-753 242

AN INVESTIGATION OF THE ACOUSTIC ENERGYOF UNDERWATER EXPLOSIONS OF GASEOUSHYDROGEN AND OXYGEN IN A GAS-WATERRESONATOR

James F. Miles, et al

Naval Postgraduate SchoolMonterey, California

1962

DISTRIBUTED BY:

Nantimia ThnclI'it• ermakmSevU. S. DEPARTMENT OF COMMERCE5285 Port Royal Road, Spdngfield Va. 22151

iI____ __ _ ____ _ i

,N" rED %TA".2NAVAL P 0-GRADU ATE: SCHOO

S0•9* ?CRADU %T'

THESIS

AN INVESTIGATIO• OF THE ACOUMSTIC Z!T"GY

OF UwDEDWATER CWLOS1ONS OF GASEOUS I1YDJWOGvN

AND O:.-IGZN Ir A GAS-WATER IESO'IATOR

by

James F. miles

and

Julian C. PatrLck, Jr.

Thesis NATIONAL TECHNICALA.58513 INFORMATION SERVICEU S Detme, of cow=0uIng4trd VA 72S•1

• .. .-- ,.- .

.1. 5..

BestAvai~lable

Copy

I "Ai INVESTIGATION OF THE ACOUSTIC ENERtGY

OF UNDETRATER EXPLUSIONS OF .GASEOUS HYDP, OSN

AND OXYGEN IN A GAS-WATER RESONATOR

James F. Miles

and

.1Julion C. PatrLck, Jr.

A

dIo

-r-- , ---- -

AN tINv STIca,•TI OF 'li . .... :" ""

OF UNDEkWATER EXPLOSION'S OF GASEOUS llYiRtOG-C*;;

AND OXY)EN IN A GAS- WATERl iRSO.MA.C0

by

James F. Hiles

Lieutenant Con•manider, Royal CanadLari Navy

and

Julian C. Patrick, Jr. M

"Lieutenant, United Staites Navy-

Submitted in partia•... .lmethe requiremencs for che degreef ,

HASTER OF" XCE I- ' IN

UnitLed Stctes Naval I r•,i':Lt_; :)ch-ooMotmrerey, Ca1lt'orsilora

Ki 1_9_62

If.,2

I _I

AN INVESTIGATION OF TIHE ACOUSTIC ENERGY

L OF UNDERWATER EXPLOSIONS OF GASEOUS HYDROGEN

AND OXYGEN i'N A GAS-WATER RESO'NATOR

by

James F. Miles

and

Julian C. Patrick, Jr.

This work is accepted as fulfilling

the thesis requirements for the degree of

MASTER OF SCIENCE

IN

ENGINEERING ELECTRONICS

from the

United States Naval Postgraduate School

Faculty Adviber

~~F Faa Ulty A -1I- fi.,rwr7;

Ch 'a r onDep~rtme.nt of E!ec.tronics

Approved:

/ !a'"di /) en t .

AciGi. t.,l

Ifl-I

Tim etCett yeers at tho U. S. Naeval h'awt~xeiduiitoOkt'.

SJo efl of interost luss br.n exhibited in the ut•' of , .>'t• V)4 l

sions in semi-enclosed chambers as an undczivater acouritic • .

The basic intent of this thesis was an LnvestLgptton o( the ,wru.nit to&

[ 8 acoustic energy available from such a controlled explotLon a•,! i•s •-

pendence on various mixtures of gas, including OXCeSs AnwcittS f ydro-

son. oRyYen and nitrogen.

The lcv onergy yields obtained were both unexpected avd divpolut-

Ing and the efficiency of conversion from chemical to acouttic výýr.y;y

was astontishingly low; so lov that the valua of the proce6s as 4 wouzr e.

of acoustic signals is considered to be oE doubtful signifiorsgck.

Frequency sp.ctra and time dom.in photographa f• iitnei cp,-lon -

and a s1tort section on varvntion of taerg"t with dp~ opf of

are included. U

'1

, it

TABIS OF CC.UTEN'TS

Tit leI1 Tnt td,,gt ion !

2. Equtpnent and Measuremente 3

3, Results 9

4. Conclusions 16

5, Rconmendat tons 16

Itiblioiraphy 17

Appendix

• I Gas Volume YeAsurematu 10

it SmpltLng Technique And Energy Computation 20

TII A Tatbulation of all Shots, Time Domain Plhotographs 23and Frequency Spectra

IV Calculetion of Chemical Energy 37

tit*

N'

_P=

l, tteoduetion.

This thesis was u 1erLalken as a direct follow-up of eome of the rc-

coawndatione made in theses cotmpleted at th3 !aval Pobtgraduuro Scht1l in

1960 and 1961. /1/, /2/

since the work dove in these thnses indicated that explosive •tdt.,ires

of oxygen and hydrogen could be obtained by controlled ,lectrolysis in

sea water and that a judicious choicc of chamber size and shupe, ex-

plosive mixture, quantity and type of excess gas end depth could result

in acoustic signals of discrete bandwidth, it was felt by the authors tbfit

further investigation of this method of generating acoustic sifrnals could

yield important results.

The authors decided that the field of acoustic energy measuremnat Utts

most important since it would lead to a knowledge of the actual :coultlft

energy aaialable and to a dotermination of tho Act' to Aco•ntic cn.ýi#y

convery'1n efficiency. in addition, tbirs aret -. vtu)y oi'v•,-3 en;wi' L

method of determining the most efficient mixture, the beat chapo of ti-to.tj-

ducer and any changes in mixture which inight be required$ tr a runctiov- :,f

depth, to rtintain efftcie7cy

Due to probleIa eacounter-d in the calLb.4tion of hy oplaores, Ir

devisim; 4 wethod of positio.lang thu hydrophone .Lth aspeit to the tc.ttv*-

ducer without Inducing seccotdary .offectns it th. syste. a.,, In :.' Is:I

degree, to poor weather conditions over a Inrje pArt of tho tro riv.il 41.-

able for experiatntatfton, it wnr not Ves~xleo ~i~e ~ ~ ~ ti-"

parameters. Since a niimpla~ tr~rnsdu&!ar was~ ~wiva~bkfe.; Avani

pert•eorts, /2/, it was used in this experitrnu •itth t'h4 I., , 1'A.1A .JC •*.. •

Ing it as results and devvlopr.nt. dfctAted. Dv to tv.. '.".: prcvfoL -

by mentioned, no changes •wtre %Niftt% 4hd the resAts ! t

are for this transducer only.

In conducting the experiments, a hydrophono va' connected to a taTpo,

recorder which received and stored the signal for later analysits in the

laboratory. Analysis was carried out using a spectrwn analyzer and oacil-

loscope for frequency and time doma.n studies. The acoustic vaergy wa

calculated by a time sampling techniquo with voltage ordinatei obtained

from the expanded trace of the mumoscope and converted to pressuro ordinatts .

through a knowledge of the characteristics of the hydrophone and tap* record-

er. The equipment, the techniques used, and the calibration procedures

followed aro mote fully discussed in the Appendices.

It would not be possible here to include the nam-s of all who have

been of assistance to us in obtaining equipment and providing guidance and

advice. We do, however, wish to extend our thanks to Professor C. F. Klal 43.

for assistance with the energy calculation method, to 1?rofba:ors L. E,

Kinsler, 0. B. Wilson and D. A. Stent. for htelpfu, sl .. ons, ro Prof::.:to.

C. Z. Msanecken for arranging the loan of the apectrwn &nalyzer, and to th].e

First Lieutenant, LCDR W. E. Walkup, who provided the boat and crew vLLhout

which it would not have been possible to cunduct the exoeritr*nts. Special

thanks go to the men of the boat crew arnd technicians of t•.h .ilectronics

staff who worked for us under sometiu.,s edver". condictos. 4t not.

2

• 'k

2. Equipmnt and Measurements.

(ta) Transducer, Gas HQta~urfix.ent aind 1f nition of typl-.'uiet

As mentioned, the explosive chamber (transducer) vda ailAbiA

from previous experiments. /2/ The transducer is shown Ln Fig. 1.

The gas volume nasauzeaec procedure used was wf.tich• ':ih

that employed by previous *xperi'owr.ters /2/ and the calibr•oton .,;ovoj

for the regulator valves used are siven in Appendix I.

Ignition of the explosion vas aetoplr~ished by p.LacLAg &,,o-,t",•

volt d.c. batteries in series across * resistance coil in thei ic lo.,O'N,

chamber. Firing current varied from 10 to 12 amperes, Ignition tim

varied from 8 to 20 see and seemed to be an increasing function of rthu

amount of excess gas.

(b) lydrophone

The hydrophone used was a BleR3a for lhtcih a ccxhvcitaiý .u!.e-

wAs available from ,40 cps to 600 cps when uxd withi 33 ,' oi 2 ,-2 '-

shielded cable. SLutc an additional 200 ft of •able had to b4 tdLid v,) .-

this short cable to reach the dapthi itt wh~ch the tests uie P-%

reciprocity calibrations ware ctie~pted,, in a tank, at stvar.iIl rrovv-t

cios between 50 and 600 cps. As might be expecttdq difficislttcia vor"

encountered with standing wavas aud aecurato results were nlot o~tiiiic d,

However, with the results that ware obtaifed ond by ccnparisw, t-,iq ;-

the substitution method with an ?11I53 hydrophoje, for vhich -ct cIlI to.

tion curve was available, a ftsu-, •,! -- of 3 t'e I volt Po ,'.,."'""

obtained for the, fr~quericy rsia~t cr Jr-rteit TIcis 1%auti~4re I volt ptr microbar given on *%•u calfL•tion curva a•g ,.rs wta!-

• ~~reasonable inl view of the extra lensth o catle. tn-vollWLv, T!.',,,......g":

of -8.5 db re 1 volt per u'Lcrol~.iv %4su." thm In

3 l

I -A

U L~MEL

LHA667tv

s SKTCH Trv~UC USED 0

all calculation*.

S {€~~C) ~l~rophon• ooJti mlln.

in measuring the acoustic energy available frow an eploston

it is necessary to fix the hydrophone at a known distance from the source

of the explosion. It is also important to know vhot.er there is any direc-

tionality In the propagation of the sound due to the traosducer confiLura-

tion or other factors, If measureswnts could be made, at svevral fixed

Sangles relative to the transducer while mstintaining a fixed dLstanc* from

it, any directionality present In the sigual should be apparent. An attempt

was made to meet these requirements by fixing the hydrophone to the end of

a boom, the other and of which was pivoted at the suspension point of the

tronsducer.

Unfortunately, it was found that with a free hanging transducer,

as was used in these exptriueAts9 the prevence of the boom had an effect on

the explosion and that this effect varkid wLt% the ;.tt'o of t1t* boom.

For instance, high frequencies (3-4 Kcs.) were observad in the output when

the boom wai vertical or close to vertical Otich werý. not pr-sent Mien t•le

hydrophone was placed in the saav position by tying it to the suxpenc in ! •t.r

and removing the boom. This indicated that the boom w-is ex:Ated to longi-

tudinall vibration by the force of the explosion ad tiv" ,w Ntgh uquanc It.s

came from the boom nnd not the trans(lucer. T •-, s . w.•i• t-, Itscar .,d

and another approtivh to the problcm of dr.rcLout. "y -. r .

The. hyds-:ýphann vas attr~c~had tr' a length of lLiuv 04!.cli! uis~ Sacured

to the suspenrion cable of the Lretisslucer; z, ict, liet;£iovl was pla<:1d oi

the hydrophono cabl to tnnure thit th,' hy'ophonr. "S p iacing fin.

4pproximately Man~ I;-ngb of ths.- line, In th,. -, tp~~ o.'uL.

tioned at s(cveral :ffer•o•tt t,)u trk!.ot'n ~ri.cJ '• .- :,. eo th4ý i V .

duecer. When the ot,;.put wave £urn-i of *xp..,'.'•, i:¶' hy, phr- .te ,!g.:

S~5

above the transducer wure co.rpared with the outiaIL" •vcW ,r•r.n of L,£•!lf ]explasions vith the hydro1 ,hc,. ,epp~o'.Ly thI .aS ,.' -_t:* ct C. okla

side of the transducer, they war• found to be quite ot!rnt" :tti-c, -.1th TC

exceptions, contained no froquancies above 6CO cpn. Since i t• kno$,nv zaý

S~little directivity can be expected from any d&vice whose trhystcr1 ftwr•.r, toci

are less than one quarter wave letgth, (approx. l1O incheis -i Y'1 cps ino s,3

water) it van apparent that the 7-1/2 inches diameter by I, Lhchws Ictsi; tr*"-

ducer could not direct the sound. On this premise, tho travte-ttc.•• r •, At

ed as a point source, radistinC sound uniformly In all diractio•it., A..A -Il

measurements were made with the hydrophone secured to the traniducar sue-

pension Ilte at a point 20 ft aibove the center of the tratsd'eei.

(d) Recording System I

Since an open boat without an electric power plont v'es coploy;.:o

as a platform froma which to condtuct the o~tunl oxp1lzs-.4; in~ wttcp;:?r? $I

.o•-. w s not possib l e to take• ana ly s .-a equ ir-t ,ct a lone . 7n iL .,_td., r ,,! 12 • " "*!cdc. to 117 volt 60 cps rotary ccnverter was used to sippy ar• A.,,. 6a

Tape Pecorder, on which vIl explosions ware recorded.

The tape recorder had a 'i.latlv-aly swAl1 dcrTAJ.4 rah~e (Ateout " -

db) and care had to be taken not to overlond the Lnrput - p...--,

overload did occur, the shot was reperted at a lowee Input T•ip, V't'. X

corder Sain charactoristtcs we- Iveatigat~ed as Euvrzticuc of Wp'ut i"

and are given in Fig. 2. In all ca•Lulatio.s aEins of lA, 18, ad 24 A, vlo;!

were used for wicrophatte input leve-ln of 3,0, LS~ ~ati 4J) m.ra

(it) An~yst

Analysis of• ta --acordio,.' expoetior, -,evfoya it.'• C.irri ,. In A

both the tiv and fre.q.t:nay ,yo ,caains, Thu outpute •f th o ta-• e,:C,1.

properly telti..t d .in a 60, Ch"s fed to 4t ,tt.•zea "'"

6 J

-M ,

- __ __ F7 .-- .- .- . . .....

I AI4t-~71 *'4.,.Il

~~~wi. . .....y. I*J4 g~

** 3 -It + P,... .. .

_'ý Li i.1__ ILI ~ :i.>!IIi.

P., h L 1

t It

_- Luj2.__1: IX :

:'1::7 -,. -I .Of. IT

I.jl i.L' '7-'iIJ ~ 1 I .i.lI .1

V1 .. i

S I17

4"4

.. D~,p .... ri ... I'

"tt ,. 4 1 j4 i..t :1....!

7L

-7'p

.An order to obtain voltage vs ti•m w aveformr, which could be convarted to

pressure vs ELife throuth a v:,•wldge of the th ap,- :ur4ur and Ir..,,yhorn...

response characteristics.

Using sampling theory, it was possible to calculate the •acouztic

energy senerated by each explosion from the pressure vs ti" v•voforms..

Appendix tt gives the theory and sn illustration of the tochnique used Ins

these calculations.

The output of the tape recorder was also fed ta'A Kay Electric

"Vibralyzer" from which an amplitude vs frequency spectrum was obtained, A

usually from 5 to 250 cps but occasionally 5 to 500 cps when the spect- 2

spraad beyond 250 cps. It was not possible to calibrate the Vibralyzer

so as to give absolute Intensity lievels, due to the complicated interaction

of the record level, reproduce level and mark level controls but relative .

amplitudes of vrominent components could be determined. The 6trplftude

scales on the spectra tn Appenftx IV are toreffore plott-o in dh bolow

the amplitude of the peak component.

It may be noted In vuiny of the time docuin plioto3 rphs, most.

noticeably in number 22, that a high frequency compo rat. if) p.'sont durfiig I

portions of the output pulse. The frequ.-ticy of this co.nporj*at was datcr- A

mined to be about 2 Kcs which is the frequency of "ringing" of te trt•.is-

ducat itself when partially filled wdth ,.6s9 sunpe'd•.d juat b;,ljw the our-

Y iface atnd hit with a harier, Since this *.:orapostent 8s Lnsai-nifttnt-..*t in Lnearly all cases, it v.ac lxnaroed in comprtin? the er.r',,' coi•.ta of the

output waveforMs. N

L E-

3-3

A~ttheu boginning of tha inveseigatiosi, it %wi k1 if A.t;

mount of gas in the chamber over end above the 4t.4tuaz OLtt w.i! . ,]

in the explosion was one of the factors controlling thl %L .,h ef ;m:. q.-

trum that would be obtained. It was also implied, if ncc t.tY,-.bta Or•

acoustic energy available from the explosions in the trars•tisitr . q~t•

large. It/ This assumption was later proven to be invalid; btit t€' itieaeti-

Xetion began with it as a basis with the intent of measuraic th•sy vti.y,

investigating any directionality of the transducer as a necessery t.tfjuvýct Co

measuring the energy and computing the chemical to acousticnl ene:!& ooov-

version efficiency.

As the investigation progressed, results were obtainrte.AJ; vi fittfica-.id

that not only the amount of excess gas buts to some extent, tlhv recri of

the excess gas was a parometer affectif. Lie acousietic encrgy c'vti, O F ?

"explosion. The author4 decided mt this roint to ncce,%tc O iht: .

In this area and to attempt to determine as nearly as possible tu.w

at one depth which would produce the veximum acoustic energy.

A transducer depth of 200 ft and a watnr depth avliyh in aet, -A,' 4,,.

ft vere selected to ntinimize surface and bottote roflecione,, . ,.

plosions were set off with varying *mounts of pure hydro..:,P C:a, :. ,,- ,..

trogan as the excess S And additional chots vor,, tidt. 'f.h vjri...:-.- !:1.

tures of these gasec ,.i €-txcess. During this serLets of shots, o4 Ur c,

combustible mixture (0..33 liter 02 nnd 0,67 liter H2 ) . .

The end results cf Lha investigation can L,,t be aprec ti!d, v',:. :.I

study ef Figures 3, 4, ti•d 5, i•iich show curves o" 4-,ot.j -:: ,•t % -t .

functf'n of qlufnrcft) of! excees ns for puire uxc-crcst, c mi , , f

excess, and veirlouis nxtemroa of excess vnpectiviIy. It In I*~ ¾ *y

9

°- .-

- -- =--- p-~

F obvlouis that the addition of excess ,As affvcta; the aoustic output tivd

that peak acoustic output• occuk: for rctos of c.c;€3: /,s to expl vSiv.i

mixture between 1.5:1 and 2:1. This peaking eftfct corrlates to some lx-

S-tent with detonation vslocities for mixtures of thuse usae gases given vua

page 80, Undervater Explosions by R. H. Cole /31.

The most surprising result of the LnvestigatLon, vat neither that a

peak 4d1 occur nor that It occurred whire it did, but thAt the acOustic

output at this peak was so mall. When it is considered that over 7000

Joules of free energy is available In the recombination of the gases In-

volved, (see Appendix IV) the conversion of lee, than one joule to acous-

tic energy given a conversion efficiency in the neighborhood of 1/100 of

one percent. When it is further considered that the spectra obtained in

the region of mximum efficiency are relatively broad compared to 0he Oar-

rower spectro obtained with less efficient axplosions, it to app.•re tnt t tha

the requireeuts of high acoustic ou•put and r 'arrow •pectrn,: al-, ,,,t:.11 4

incompatible, at least for the particular transducer used in these tests. ,

tn any case the very low acoustic efficiency indicates tha procL .a in of

doubtful value as a source of high intensity ocoustic signals.

Although the study of the spectra involve• it thin o explosious has

already been well covered 12/, the titi dowain pcturos. frequency ospctraSa~~nod a tabulation of acoustic energy content ar* i.nlud~d in ApptndtX .T11•

for those interested in studying th. Ti• co•ten•t piictur hadw ap rdt .-.i

converted to pressure In nvwutons/r. er and abser.nsn -Lven it milli-ee.-e.;A.

while the frequency spectr4 ordinnter give relative powtr la . bT41 " ;

the power in the strongest freqe.ncy cowponent.

A brief study of acoustic onergy As a fun•ctLi•n of depth wase .

For a r.tngl¢ mixture, thot, wero cor,•ntced .t. 200c 175• 15to 125, .and !a•j

10

r

- -T~l~ r ~7I 7 .-***-I I~ :,~:T,

41)..: :I.I.41

0 .0 c +d

.. . . .. . .......

i,,:.~ 71 ;1!H! .. . . .. ,.1.

tI'I

.: . . . .. v-

___ F.:

11

C ...... .. ....

*f *.T7* ..j:. - .~ *. ..*

-.4 1. N " '.

II..

Iii

ifti

[t -. '......I._:.

to ......

el *j f~j Z...............t:. it .;t m. I .2:L:

Vr J . .I. . - -.: ._: *1 19~ .. I A-~ ., ,

!:' .. . ..

ET Im H. J. u~

11%

7 -.. 9..

I t ~

_~~~~~~~ .... I.t' ... -. .+ . ..;Ili Ito jI4 941 "if ' I J l I~ ; :~~CZI~~~~~ :T::,i h W~ ' ~ 1 ~ v 9

u) 14 71 Z.-. **9 .- 2,

9,;..&. 7f

t~j 0 9. lil

Ix~~~ U)1 .; ),u

4ý) 1 41 i ;ýiT2]7Thl. till -E-4''lI 00L.:'K. .~ j - 994* '' 9::

'9~~~~~~~~~~~~~~i 21.............................. 1N 7.H ",. . .0 H--:' 0 H X: j.99lot,

14 A . 1.

7113

arc plotted In Wi•. 6 whieh tndic~t.m that thmre Lc to, signiftcant vArx-

ation over the range ot depths investLgated.

nlteresting, though not Important, results were obtained in the ex-

plosions which contained oxygen as the excess gas (Appendix IV), nu••bers

37 to 41). The pulse was approximately the same pressure level as the

excess hydrogen and nitrogen shots, but was of very short durstUhn Iv

some cases only one or two cycles of oscflation.

1

4 I? F

•14

,

________ ,.t2t.-.

0 41 :T. 4 *

I :~;i. "'~ .4 *. ;~t..: t'r~4~1;8. ~L 1 ~t72 . .iTl

C::t 1::

a'' 4- 4

(04-1t I -

N2 E- E

r -.1 1..11

94 4 ER:1q

.j 4 . i I f;, 0 I-- I - , Ij-C

1v,4 1 Ittv.

.. ....

4 !t;

(a) Acowu'tt eaecgy content is a function of exie.-s gatr t u ..,%-

plosive mixture and varies with the nature of the excess gSiss

(b) As a function of the amount of e*cess gas, the range ovr uwht-ch

maxim•m acoustic energy is obtained does not correspond with t'he• rrtfi

over which the narrow bandwidth desired is obtained. Therefore, for ctil.

transducer used, these two desirable characteristics arm io~psitil,

(c) Chemical to acoustic energy conversion efficiencies are: exttrvne-

ly low in the transducer used in these experiments. Peak efficlecey oh-

tained was of the order of 1/100 of one percent.

(d) The efficiency of the process, using bottled $•s or in ctus-

Junction with a hydrolysis process, is so low that its value as .4 4oure:

of high intensity acoustic signals is extremely doubtful.

S. Recomandations.

(a) No further work should be done in this field at the L: US. .,av::!

Postgraduate School unless theoretical studies indicdte a transducer 4-

sign, gas mixture or detonation method which would improvoe the conv~rtLzn

efficiency by at l.eadt 3 ordars of nrgnitude.

(b) Tn the event th~t firther york is authorized, a r-re :utti.blu

boat with an internal power supply and equipped with sLX.olti r•,!'-r

winches should bo provided as a platform from which to couduc, the ti'vtr.

! -

1

SIULt.tOGI'AI'Iri'

J. R. HarrsL and C. M. Rigabee, An investigation of the F•iw-rSpectrum of Underwater Explosions of Caseous Hydrogen aud C)ygon,U. S. Naval Postgraduate School, 1960. (ConCidential)

2. A. D. KeLmigs Jr., and J. L. Hofsockel, Frequency Analysts ofUnder•ater Explosions in a Cas-Water Resonator,, 1, S. NavalPostgraduate School, 1961. (Confidential)

3. Re. H. Cole, Underwater Explosions, Princeton University Press,1950.

4. L. E. Kinsler and A. R. Prey, Fundamentals of Acoustics, JohnWiley & %ono; Inc., 1962.

5. H4. A. Paul, Principles of Chemical Thermo-Dynamics,, McGraw-Xid Book Co., Inc., 1951.

NI

17

-g'il4*2

CAS VOLUME HASURK"IMTS'-

The tuchnque of metering the gas Liwto the *xplostve . ,...

developed by previous experimenters. /2/ The calibratiort curvaoe for

tim reViletor valves used are shon in Fio 7 vhere tho ordiat&. is

mlHI.-liters of gas and the abscissa is gas pressure in eh.* high V.r"cre

Wsug. of the valve.

A

18I

r I

I..I is

77 J-1 IM

84 __ 1i l4. ++r

...

M11, l it 4: t * F I

_.._ I

tit~~~. 1i : -i -I . It"

.......... ~.. ----- f-,f~ .u .4.

C;t~f .1 1__

4' ~ i . . .4

:rl flu

Li .' .. 4 .4

LL:J. T

5'7

E4 ;4jrqp .. ... ... ....! 8 2 .::j~ 4~ 0~jE-4 V4, ..I ... .i~ ~ ~ :; I 1s.

LI I111 I:t lilt II

41 It -

___1__________I_____L_

r 7__7___4

APFEK•DI) !T

SAWPUM- 17.CP, NIQUE AND ENEIGY C•Otl'T%•.••i

As owntioned in the text and other appendices. LtE VAv% fOr-1.15 of

the explos.ve signals were displayed on the 'augt.*s o4o-seople. Orn...ea

were then r•corded every At seconds where At is dcffined a.s follows:

If any complex wave form be sampled at a rate ouch thr't the number

of samples is '2"Wti where T ie the length of the signal if the

signal is non-periodic and is the period if the sigul has periocd.iy

and where Ls defined as twice the highesc signiflCant frequenc'" CoW-

ponent, then sampling theory states that. the wave form may be ret~ro luced

from these ordinates to an excellent degree of accuracy. If woe assume

that Ns is much greater than one then the number of samples becomes

SZTW and the samplirng interval is T * the length of the p•lse., divid-

ed by •TW9 the number of sample ordinaten; this n.rplins f- 4 iv is is

that A which was to be defined.

From sampling theory we also knou that the energy In the pulae is

given by

Energy IV*Awhere . V;1 Is the simovation of th: eqtsares o* the save.ral .Rovpled

also to be taken e':rons a one oh.a load, Frcsi, the 8aln , .L.fcs

of the tape recorder, the rexponse ch .:ceterfdcice of tbz r ,,i~vn Ihydrophoue and spherical divergence for thit knowii spewing• . hydro° i

phone and transducer, the voltekc orcrntes vlay bf r•.-'voxi'd t'•) o's¢.

pressure ordinaten. Acoustllc energy in the ayploip.-t -r. : ie n'aJ'

then be comnputed frot. the rt•.lst.ioz -

4•7eay A t,

atLg, * llae quf*irttty (ec to the Acs*'ntA. -~'c: .~f 'ita Wcer

and the term d4r servos to integrate over th. sttn-rd sfaftre -,f ore

meter radius. Here it is asguwed that there is no dUrotivity, 'n

assumption that is reasonablit for the frequencies involvad And one

that was to some desrta verified by observation.

Now, compute the conversion constant which converts vo!tae scuareV

to acoustic pressure squared. Assume one volt out of the tape re.der

at a microphone input level setting of four (24 db gain). The taput

would then be 24 db below ore volt; and. assuming the receLvin!s hty'ro-

phono to be flat at -85 db te I volt per miteobar, the soatd preaoure

level at 20 ft is

SPL = -24 - ( -85)- 61 db.

Allovi,$ for spherical diver$wijt~ to find the source levt ( ove.t

SL - 61 + 20 log r ( r it v4!ter6.)

SL -61 420 log 6.10. 767 db.

From the relation between source level and pressure

SL a 20 log 10 P4 (Where rP4 is alccusti, iCasu.in .eOtons per squ."re

The pressl'oe equivalent of I volt is

2P4 - 684 Newtons/neters /volt.

squazing this cousteait yieldo

2 2 4 24 -, 4.68 x 10 Nflewtons /m*.ters /volts

Similar calculations for microphone (nput 1evelts of the.r ( 4% %,, i 'a.

and three end one-half ( 18 dh gain) gave as v~lue8 for P %A. '?

2 6 2 4 2P3 7.41 x 10 ROWCo1s /mvters /Velts -

P3 2,72r x 10 3 1I,:,ron;/f-.rof,2 'lolt.

, 2 4 2

35i .fl70 x 10' Netn;/e-3c ct

322

P , 1.•70 x 105 1wtcvtqh/w•.ts•-. /volt,•P3.5i

717r ;ov w fo r a ny g *v .' - - • ,; ,: ,' ': ,. u L t u ' I . •.• r isk- • :tu- -gy ,

thm pulzu Ls[ tEnergy

aud the intivintrrti:tc-u- peak power is

(OC

A tablatiotn for all shots is Sgiven Wi Appentlib: tt.

L1

?I

-- 4

I

22

AM=YMfY Is Al

A TABUIATION Of ALL SHOTS, TIME DON•l[

?IIOIOGRAr1S AIMD FRITEt.NCY SPECTRA

This appendix Ls a tabultion of all shots. Table I iuclud•a shot

number, d*ts shot jde, n ature and quantity of excess gas. Lnatat•tf:AnGOuj

peak acoustic power and total acoustic energy. Time dovAin phot:ograpbs

and frequency spectra for each srot in Table I are also shown.

to the time donsn photnsraphs the ordinate is given• in 'ne, ttif2Fmeter per division and the abscissa in mulli-seconds per divIsion.

to the frequency spectra the ordinate is in decibels belov the peek

component and the abscissa itn cycles per second.

4 3

23

r S

.TAB LE T

Shot Date Excean Gas Instantac:0,w IN Lof N2 Peak Acoustcic ACOUSCLc

Shot PowerLiters Liters Watts Joules.

1 21 Feb. 3.0 5.5 .051

2 7 Mar. 3.0 - 11 .093

3 7Mer. 2.5 - 36.7 .248

4 13 Mar. 2.25 - 137 .458

5 23 Feb. 2.0 -88 .580

6 7 Mar 2.0 - 107 .562

7 13 Mar. 1.75 - 146 .690

6 7 Mer. 1.5 - 137 .612

9 13 Mar. 1.5 - 146 .647

10 13 Mar. 1.25 - 208.5 .544

11 28 Feb 1.0 - 55.3 .196

12 21 Feb. - 3.0 ii.7 .066

13 7 HMr. 3.0 12.4 .138

14 7 Mar. - 2.5 8.6 .036

1s 27 Mar. - 2.0 23.0 .125

i6 13 MAr. - 2.0 2q.9 .252

17 13 Mar. - 1.75 91.6 .471

18 7 NHr. - !,5 95 53)1

19 13 Mar. - 1.5 87,6 .509

20 13 Mar. - 1.25 156 .518

21 28 Feb. - 1.0 55.3 .212

24

TABj- I ( Out)

Shot Dmtk! Excesas 4,6 1Sof 12 02 Pe a'ek At;oustic Acm., i.-

Shot Power ao ....Liters LUteri Liters Watts 3oal- -

22 7 liar. 0.5 0.5 40.6 .049

23 7 Har. 1.0 O.S 102.7 .359

24 7 Mar. 0.5 1.0 146.8 .469

2S 7 liar. 1.5 0.5 74 .514

26 28 Feb. 1.0 - 1.0 55.3 .442

27 28 Feb. 0.5 - 1.5 39.3 .203

28 7 War. 2.0 - 0.5 21.2 177

29 1 %or. 1.5 - 1.0 11.75 'I11

30 7 Mar. 1.0 - 1.5 59.5 .130

31 7 Mar. 0.5 - 2.0 13.8 .171

32 7 Her. 2.5 - .5 8.34 .135

33 7 Mar. 2.0 - Il0 9.82 .133

34 7 Mar. 1.5 - 1.5 8.,02 ,120

35 28 'Feb. 1.0 - 2.0 13.8 ,151.

36 28 Teb. 0.5 - 2.5 11.1

37 28 Feb. - 0.5 1.5 32.4 2138 28 Feb. - 0.5 2.5 9.A2 ,Ina

39 28 Feb. - 1.0 1.0 55.3 .198

i40 28 Feb. - 1.0 2.o 6.4b .04 i

41 27 Feb. 3.0 9.82 .073

42 21 Ft, -

N ote: All sbots contaitn 0.67 liter H 2 anid 0.33 t."02 1 A I Uo

excess shon.n Shot umrber 42 not #e•pieo.J

25

o-4

.342 newtons/mý/div. SHOT VO. I

.62 90 A4?/ Ii0

34~2 wtne3tfs/m2/div. S~c~;.2

f 7Z

d-* -I ;g-

684 newthns/n 2 iv.£-V O

20 rrsec/dIiv. newtos/iI

All.t•q

0,

..0 moos c/.v.^ fro.quenc.-(clps)

9.. t. 4.&-.

. . . . .. .

136P nowtons/rW2 /iv. SHOT w.0. 6

C) WII- -n- v- .,

13&S newtona/r:2/liv. SH!OT Nt0. 7

Iv-

138 rtons/..&/'.iv.

-�•r�-�---�------'-- -. - ---.= - ---- -�-- - - --- ---- - -

- - - -

-- - -. - a

-1

.* � ..

�.U t1��5�I

Gd

-�*

-,

fre.v'�r�cy-( crs)v�.'wt,' �:' ''./i!v. ThG� .0. 9

[ j

Q�.

4 a

*., �4'&.*��'f4$�P.�

-,�.1 -I

�' I! ar *�'0

II..I'�#

-

r?..� -:2.-II

.� I rt J

-I.:,-

* jp

*- -�

I, * 1-.

4.. aj�.........t

a.Lj' � 1 * I

& .- , 'I

U)� I ga

.t

1* �..J-

I. ILI

'a

1) .I::.� I

S. *-'

-�

* .. .�*

C.,

-- -- �- -�--�

---- �-

----- 1--ILI

d-4

e. 4 --

-AA

20 Ta.sec /riv, rqec-cs342 newtonosfr 2/div. SHOT 111. 13

20 i,.e1lv680 wa.orec/div feqencU(ps

..'~ ..... .

wI

db-INh

20 z-a rc/ a v.h W fL Leuen y-.Zs' LI

684 newtons/m2 fdiv. SHlOT NO. 17

C-4

20 m~sec/Iiv. r.c (c )684 newtons/m:'/div. SPOT :.1

or3

liei

20 *' ~e/.:iiv. frequzency-(cps)684 nc:wtons/m 2 /div. SHO)T r%.-:. 19

:'20 m.sec/.J1.v.

iv,

- II

-h'

freqtiency-( cfs)

"120 m.see/div. freqluency-(cjps)1368 njeiwtons/nq2/dJiv. SHOT NO. .23

[I

1XV. A , .

20 ~se/di. rc2ueny-(vs

U 368 lbewtons/r?/iv ~ iIOTvo 2 ~':!,) ". 2

'o~l,

aA241ý; 41A0~ ~ "

30 m-sec/dIiv. frequency-O(ps)684 newtons/m 2/div. SPOT 11O1. 25

J

-1AI

68 atnsý/jv. S l Oý 1:. 26 o ** i~ :

20 ui. sec/div. fre.quency-(cps)684 newtons/ 2 iv 0HO i. 26

A2~~ n*.'--! ,2J iv...2

20 ~sc/iv.fr:;eny:(:32,a

12- If

20 ri.sec/div. - frequency-(cps)342 newtons/rn 2/dtv.- SHOT WO. 29

*1M

0920 a

.-'.O *,0 31~.

Ft ~~ I 1 4 .t

-eg . ntt jt V 'na HtA . nsq

/**Z4of

0

AA.

wc~Co

2q ,V .. f. I iR

CL -20 -J4CL

W. sac0di fruency-c~

3,42 nivatons/rn"VJiv. SHTU.33

20 rm.scC div. fre~-uncy-( Cps)2342 fL..,~'iv. ThTY.35

OdII

29. m. sec/div. rc~~c-c"I 42ne'dtons//dv I m, OT±. 35

I-n

I ep

F20 L..sec/liv. fre',uency-(Cps)68 etn/m2/div SHIOT NO. 37

2/i,. 'OT -0

fir..

dodJ~

34 40

20 w.see/dive frequecy-tes) ju

342 riewtons/m2/div. SHOT NO. 41

d6i

iC insec/iv. requency-(cps)684 SH ~/a 2 iv OT NO. 42

APPNIX IV

CALCULATIOW OF CaIiCAL EN4r(Y

Here it is assumed that the recombination of the hydrogen and oxygen

takes place in such a maner that gaseous water is for d initially Ar-d

that the heat of combustion of this reaction is the available chemical

energy. n reaction is:

where • is the beat of €coewetion in cal./sole and is equil to 57,800

cal/sole.

One liter of combustible mixture ( 0.33 02 and 0.67 E2 ) was mtan-

tained. Assuaing that hydrogen and oxygen are ideal gs&es ( 22.4 liter?/

sole ), there is 0.0299 mole of hydrogen and 0.0149 moles of oxygen. The

reaction will yield 0.0299 moles of water vapor and 1728 caloric. of beat.

Converting calories to Joules gives 7260 Joules. The value of 7260 Jou.;es

was used as the chemical energy in computing the chemical to acoustic

energy conversion efficienciss.

37