ACTA UNIVERSITATIS APULENSIS No 9/2005 CALCULATION OF THE CRITICAL STOKES NUMBER FOR WIDE-STREAM IMPACTION OF POTENTIAL FLOW OVER SYMMETRIC ARC-NOSED COLLECTORS

The wide-stream impaction on a class of semi-infinite twodimensional symmetric bodies having flat or circular-arc noses placed in a uniform potential flow of aerosols is investigated. The governing Stokes equations of motion are nonlinear differential equations involving a parameter called the Stokes number. The study calculates analytically the critical value of the Stokes number on the centre-line, kcr, below which no particles reach the stagnation point in a finite time. This in turn can help the experimentalist in designing appropriate collector shapes for obtaining a better collection of small aerosol particles.