6926475953

wiwi by a ahip fłxed at ha maan edwncing poałtton. In an Innar region ciota to tha ahlp tha hull geometria! tlender-naaa it uaad to juatWy a qua*Hwo-dimensk>ngl approximation of tha fkm. Tha mathod of matchad atymptotk axpanaiona la than introducad to anforca tha competfcllKy of tha innar aolutlon with tha three-dimentk>nel aolution |n tha far flald. Tha thaory ia ahown to ba unWormły valid for all wevełength» of practical intaraat and all anglaa of wave incidanca.

aiva noiaa and blede-vortex intaraction impuliiwe noiaa. A thorough phyaical expłanation of both ganarating macha-nlama ia praaanted together with model and full-acala mae-auramants of tha phtnomena. Currant theoretkal prediction mathoda ara comparad with axparimantal finding* of iao-lat ad rotor taata.

84-1615

A Numerical Sohitiou of Two-Pimnnaiołui Deep W a ter Wave-Body Probierni

A. Nestegard and P.D. Sclavounos

Massachusetts Inst. of Tech., Cambridge, MA, J. Ship

Res- 28 (II. pp 48-54 (Mar 1984) 13 figt. 14 refs

Kay Worda: Intaraction: ctructura-fluid, Shipa, Wava forcaa

A numarical tachniqua ia praaanted for tha aolution of daap wat ar linaar and t ima-harmonie wava-body-intaraction problem* In two d im an sio na. A mathamatical boundary of circular shape aurrounding tha body ia introducad in tha fluid domein. thua defining two fk>w region*. A mułtipole expenałon walld in tha outar ragion ia than matchad to an integral rapraaantation of tha aolution in tha innar ragion which ia obtainad by applying Graan'a thaoram and by uaing tha fundamenta! logarithmic singuiarłty aa tha Green function. Tha mathod appliaa both to aurfaca-piarcing and aubmargad bodiea. Numarical raaułtt ara praaanted for tha forcad oaciiiationa of three aurfaca-piarcing rftip-like aactions of reguler ahapa.

84-1617

Rotor/Body Aerodynamic Interacbona

M.D. Betzina, C.A. Smith, and P. Shinoda NASA Ames Res. Ctr., Moffett Field, CA. Rept. No. NASA-A-9500, NASA-TM-85844. 39 pp (Oct 1983)

AD-A135 040

Kay Worda: Halicoptara, Rotora, Propallar blada*. Wind tunnel taating, Aerodynamic load*

A wind-tunnel invaatigation wat conductad in which independent, ataady-atsta aerodynamic forcaa and moment* wara maaturad on a 2.24-m-diam, two-bladad halicoptar rotor and on eeveral different bodiea. The objective waa to detar* mina tha mutual intaraction affacta for ariations in ystocity, thruat, tip-path-piane angla of attaefc, body angla of attack, rotor/body poałtion, and body geometry. Thia report pra-aentt tha affacta of vark>us paramatara on tha interactiona and diacusaaa tha difftcutties ancountered in determining tha affact of tha body on tha rotor performance.

AIRCRAFT

(AlaoaseNo. 1653)

84-1616

Hełkopter Iropnbnre Noiee: Uteoretkal and Experi-mentaJ Status

F.H. Schmitz and Y.H. Yu

NASA Ames Res. Ctr., Moffett Field, CA, Rept. No. NASA-A-9477, NASA-TM-84390, USAAVRADCOM-TR-83-A-2,105 pp (Nov 1983)

AD-A136 987

Kay Worda: Hatkopter noiaa

Tha thaoretlcal and exparłmemsl atatua of haticoptar impul-•iv# noiaa ia rev lewad. Tha two major aource mac han lama of halicoptar knpulałwa noiaa ara eddreased: high-apaad knpul-

84-1618

Adaptfre Inyerac Contro! for Hdicopter Vibratk>n Reduction

S.A. Jacklin

NASA Ames Res. Ctr., Moffett Field, CA. Rept. No. NASA-TM-84336,19 pp (Sept 1983)

N84-11177

Kay Worda: Halicoptar vibrat»n, Vibratk>n control

Tha reduction or allawiation of halicoptar vibratk>n will raduca meintenence requirement« whila at tha aame tima i ner aa aa rida qualłty and heiicopter reltabilłty. In forward flight, tha halicoptar'! fuaaiaga v»>ration tpectrum tandt to ba dominatad by multiplet of tha N/REV componant. A way to uaa tha mathod of adaptłva inwerae control to kJen-tłfy, in raal-tima, a controllar capabla of ganarating N/REV yibration of oppoaita phaaa to cancai tha uncontrollad N/REV componant it praaanted. Multkydk faetharing of blade phch li tha control contidered.