Determination of air and hydrofoil pressure coefficient by laser doppler anemometry

Some results of experiments performed in water cavitation tunnel are presented. Pressure coefficient (Cp) was experimentally determined by Laser Doppler Anemometry (LDA) measurements. Two models were tested: model of airplane G4 (Super Galeb) and hydrofoil of high speed axial pump. These models are not prepared for conventional pressure measurements, so that LDA is applied for Cp determination. Numerical results were obtained using a code for average Navier-Stokes equations solutions. Comparisons between computational and experimental results prove the effectiveness of the LDA. The advantages and disadvantages of LDA application are discussed. Flow visualization was made by air bubbles. U radu su prikazani rezultati eksperimentalnih istrazivanja u vodenokavitacionom tunelu, u kojima je odredjen koeficijent pritiska (Cp) pomocu laser dopler anemometrije (LDA). Ispitana su dva modela: model aviona G4 (Super Galeb) i model hidroprofila lopatica brzohode osne pumpe. Ovi modeli nisu pripremljeni za klasicna merenja raspodele pritiska, pa je za odredjivanje Cp koriscena LDA. Numericka simulacija je izvrsena softverskim paketom na bazi usrednjenih Navije - Stoksovih jednacina. Uporedjenje izmedju numerickih i eksperimentalnih rezultata potvrdjuje efikasnost LDA metode. U radu se razmatraju prednosti i nedostaci primene LDA. Vizualizacija strujanja je izvrsena mehuricima vazduha.