Control of Sheet Cavitation by Injection

Abstract

It is well-known that sheet cavitation inception is dependent on laminar separation. Therefore , the sheet cavitation might be controlled by restraining the separation. Authors tried to control sheet cavitation on an axisymmetric body by water jet injection, and proved experimentally that it was possible to suppress the sheet cavity. The nondimensional injection flow rate for the cavity suppression depended only on Reynolds number. The leading edge of the sheet cavity coincided with separation point which was visualized by oil film method. By increasing injection rate the reattachment point of separation bubble moved upstream and finally the separation bubble vanished. The sheet cavitation also vanished at the same condition. Žå ‚È ‹L • † ƒÀ:•• ‚«•o ‚µƒXƒŠƒb ƒg çt (mm) D:ŽŽ OE± 'Ì '¼OEa (mm) DJ:•• ‚«•o ‚µ•" ‚Ì '¼OEa (mm) Q:•• ‚«•o ‚µ-¬-Ê (l/min) Re:ƒOE ƒCƒm ƒ‹ ƒY•" Re= Tw:•… ‰· (•Ž) mJ:•• ‚« •o ‚µ•½‹Ï-¬ '¬ (m/sec) ƒÐ • ‡:ˆê-l-¬ '¬ (m/sec) ƒ¿/ƒ¿s:‹ó ‹CŠÜ-L-Ê (%) ƒÐ:ƒL ƒƒ ƒrƒe•[ ƒVƒ ‡ƒ"•" ƒÐ= 1 •• OE¾ ƒV•[ ƒg•EƒLƒƒƒrƒe •[ ƒVƒ ‡ƒ\ ‚Ì •‰• ¶ ‚ª ‹« ŠE'w"•-£ ‚AE-§•Ú ‚ÈŠÖOEW ‚ª ‚ ‚é ‚± ‚AE ‚Í ‚ae ‚-'m ‚ç‚ê ‚Ä‚¢ ‚é•B'w-¬ "•-£ ‚ð • ¶ ‚ ¶ ‚Ä‚¢ ‚镨 'Ì ‚ł͈³‚ł͈³-Í ‚Ì 'á ‰º‚É"º ‚Á‚Ä,‚Ü ‚¸"‚¸"•-£-A‚Ì •Ä•t '… "_•t ‹ß ‚ɃLƒƒƒrƒe ƒB ‚ª OE» ‚í ‚ê,‚³ ‚ç‚Ɉ³-Í ‚ª ‰º ‚ª ‚é ‚AE ƒLƒƒ ƒrƒe ƒB‚Í •¬'· ‚µ‚Ä"•-£-A‚ð-ž ‚½‚µ,ˆÀ 'è ‚ÈƒV•[ ƒg•E ƒLƒƒƒrƒe ƒB ‚ð OE`•¬‚· ‚é•B ‚±‚Ì Žž,‰½ ‚ç‚©‚Ì •û-@‚Å"•-£ ‚Ì "-• ¶ ‚ð-hŽ~‚Å‚«‚ê ‚Î,ƒV •[ ƒg•EƒLƒƒƒrƒe ƒB‚ª • ¶ ‚ ¶‚È‚¢ ‰Â "\ •« ‚ª ‚ ‚é•B‹« ŠE'w‚Ì 'w-¬ "•-£ ‚𠉽 ‚ç ‚©‚Ì •û-@‚Å‚¨‚³@‚Å‚¨‚³ ‚¦,ƒL ƒƒ ƒrƒe•[ ƒVƒ ‡ƒ"‚Ì "-• ¶ ‚ð-} • § ‚µ ‚ae ‚¤‚AE ‚¢ ‚¤‚±‚Ì ‚ae ‚¤‚ÈŽŽ‚Ý‚Í,‚± ‚ê ‚Ü‚Å‚É ‚à‚¢ ‚-‚‚©•s ‚í ‚ê ‚Ä‚¢ ‚é•B ‚»‚ê ‚ç‚Í,ƒg ƒŠƒbƒvƒ• ƒCƒ",ƒ| ƒŠƒ}•• •o ‚µ ‚È ‚Ç‚Å‚ ‚é1),2)¡ ‚Ü‚½ƒo ƒuƒ‹ •EƒLƒƒƒrƒe •[ ƒV)ƒ" ‚ª "-• ¶ ‚· ‚é ‚AE,‚» ‚ê ‚É‚ae ‚èƒV•[ ƒg•EƒLƒƒƒrƒe •[ ƒVƒ ‡ƒ"‚Ì "-• ¶ ‚ª-}• §‚³ ‚ê ‚é ‚AE‚µ‚½ •ñ •• ‚à‚ ‚é3)¡ •^ ‰h "c ‚Í ‰~ 'OE‚AE-ƒ OE^ ‚É‹z ‚¢ •ž ‚Ý‚AE •• ‚« •o ‚µ‚ð "K-p ‚µ, ‚¢‚¸‚ê‚¢‚¸‚ê ‚à‚ ‚é'ö "xƒLƒƒƒrƒe •[ ƒVƒ ‡ƒ\‚ð-} • § ‚· ‚éOEø ‰Ê ‚ª ‚ ‚é ‚± ‚AE ‚ð OE© •o ‚µ‚Ä‚¢ ‚é4)¡ '˜ ŽÒ‚ç‚Í,'Î •Û‚ð ƒV•[ ƒg•E ƒLƒƒƒrƒe •[ ƒVƒ ‡ƒ\‚ÉOEÀ 'è ‚µ, •• ‚« •o ‚µ ‚É‚ae ‚è'w-¬ "•-£ ‚Ì • § OEä ‚ð •s ‚¢,ƒL ƒƒƒrƒe •[ ƒVƒ ‡ ƒ"‚Ì-} • § ‚ð ŽŽ‚Ý‚½•B•• ‚« •o ‚µŽŽOE± 'Ì ‚AE‚µ‚Ä‚Í,•ae '[ ‚ª ‚Ù ‚Ú"¼‰~ ‹… ‚Ì Ž²'Î •Ì 'Ì ‚Å,‚» ‚Ì •ae'[ ‚ÉŽ²'Î •Ì ‚É•…‚ð•• ‚«•o ‚· ƒXƒŠƒb ƒg‚ð •Ý‚¯ ‚½‚à ‚Ì ‚ð-p‚¢ ‚½•B ‚» ‚µ‚Ä,•• ‚«•o ‚µ-Ê,ƒL ƒƒƒrƒe •[ ƒVƒ ‡ƒ"i•",ƒOE ƒCƒm ƒ‹ ƒY •" ‚È‚Ç‚Ì •"-Ê ‚Ì ƒL ƒƒƒrƒe ƒB•Á-Å‚É‹y ‚Ú‚· ‰e ‹¿ ‚ð '² ‚× ‚½•B ‚³ ‚ç‚É,ƒL ƒƒ ƒrƒe ƒB‚Ì-³ ‚¢•ó 'Ô‚Å‚Ì •• ‚«•o ‚µ‚É ‚ae‚é"•-£ ‚Ì •Ï ‰» ‚ð,-û-OE-@ ‚AEƒgƒOE •[ ƒT-@‚É ‚ae‚é‰Â Ž‹‰» ŽÀ OE± ‚AE ‹« ŠE'wOEvŽZ‚É ‚ae ‚è'² ‚×,ƒL ƒƒ ƒrƒe ƒB •Á-Å‚Ì ‹@•\ ‚ɂ‚¢ ‚Ä•l Ž@ ‚µ‚½¡