... effects on more complex geometries. 13 08 2009 16 10 2009 15 11 2010 15 11 2010 blades boundary layers computational fluid dynamics flow separation flow simulation geometry laminar to turbulent transitions turbines turbulence The flowfield found in low pressure...

...Alan D. Henderson; Gregory J. Walker Laminar-turbulent transition behavior is studied near the leading edge of an outlet stator blade in a low-speed 1.5-stage axial-flow research compressor. The stator is a typical controlled diffusion design with a circular arc leading edge profile. Slow-response...

... flow separation gas turbines heat transfer jets laminar to turbulent transitions plates (structures) rods (structures) wakes wind tunnels 08 06 2007 28 06 2007 22 01 2009 rms velocity perturbation, u ′ , and intermittency, γ , for a turbulent patch...

...Alan D. Henderson; Gregory J. Walker; Jeremy D. Hughes Wake-induced laminar-turbulent transition is studied at the leading edge of a C4-section compressor stator blade in a 1.5-stage axial compressor. Surface hot-film sensor observations are interpreted with the aid of numerical solutions from...

... position of time ( t ∕ τ 0 = 0.0 ) has been presented. A ratio of 1:1.5 is similar to that found in many LP turbines. 27 06 2006 15 01 2007 29 02 2008 boundary layer turbulence laminar to turbulent transitions gas turbines blades laser Doppler anemometry...

... not affect the flow field within and immediately downstream of the separation bubble. The process of laminar-to-turbulent transition in a separation bubble shares characteristics with both attached boundary layers and free shear layers. The Tollmien-Schlichting (T-S) instability, typically associated...

... 10.1115/1.1861914 , 127 , p. 507 . Mayle , R. E. , 1991 , “ The Role of Laminar-Turbulent Transition in Gas Turbine Engines ,” ASME J. Turbomach. 0889-504X , 113 , p. 509 . Johnson , M. W. , and Ercan , A. H. , 1999 , “ A Physical Model for Bypass Transition ,” Int. J...

... ) 31 07 2006 31 07 2006 compressors boundary layer turbulence laminar to turbulent transitions flow visualisation computational fluid dynamics wakes blades Current compressor design-tools are commonly based on studies of the flow within cascades, where the incoming flow...

.... 10 – 17 . Steelant , J. and Dick , E. , 2001 , “ Modeling of Laminar-Turbulent Transition for High Freestream Turbulence ,” J. Fluids Eng. 0098-2202 10.1115/1.1340623 , 123 , pp. 22 – 30 . Menter , F. R. , Langtry , R. B. , Likki , S. R. , Suzen , Y. B...

... requires that sources of loss be better understood. Entropy generation minimization (EGM) is a method of thermodynamic optimization of real systems that owe their thermodynamic imperfections to heat transfer, fluid flow, and mass transfer irreversibilities ( 1 ). laminar to turbulent transitions...

... turbulence turbines blades laminar to turbulent transitions Bypass transition from the laminar to the turbulent state occurs when the linear growth of Tollmien–Schlichting waves, preceding natural transition, is bypassed by the penetration of disturbances into the boundary layer from a highly...

... of transition Mayle , R. E. , 1991 , “ The Role of Laminar-Turbulent Transition in Gas Turbine Engines ,” ASME J. Turbomach. 0889-504X , 113 , pp. 509 – 537 . Rivir , R. B. , 1996 , “ Transition on Turbine Blades and Cascades at Low Reynolds Numbers ,” AIAA Paper No. 96–2079...

... laminar to turbulent transitions boundary layer turbulence flow measurement heat transfer friction It has been well known that boundary layer transition from laminar to turbulent flows starts by the random formation of localized turbulent regions known as “turbulent spots.” These turbulent...

... laser Doppler anemometry laminar to turbulent transitions The unsteady flow field in low-pressure (LP) turbines is governed by a combination of potential and convective interactions 1 . Of these, the convected wakes from upstream blade rows play the most...

...P. M. Byvaltsev, Researcher,; K. Kawaike, Chief Researcher, A comparative study of two transition zone models was carried out to assess their ability to simulate boundary layer laminar-turbulent transition. Transition modeling is based on the use of an algebraic equation for the intermittency...

... quantifying their combined effect on heat transfer and laminar-turbulent transition. In complementary studies a trip wire is used on the suction side in order to fix the transition location close to the stagnation point, thereby allowing a deeper insight into the effect of roughness on the turbulent boundary...

... reattachment region are well represented by Narasimha’s universal intermittency distribution, lending support to the use of intermittency-based predictive routines in calculations of blade boundary layers. Mayle , R. E. , 1991 , “ The Role of Laminar-Turbulent Transition in Gas Turbines ,” ASME J...

... , “ Modeling of Flow Transition Using an Intermittency Transport Equation ,” ASME J. Fluids Eng. , 122 , pp. 273 – 284 . Steelant , J. , and Dick , E. , 2001 , “ Modeling of Laminar-Turbulent Transition for High Freestream Turbulence ,” ASME J. Fluids Eng. , 123 , pp. 22 – 30...

... from the thermal boundary layer is longer than that from the momentum boundary layer at favorable pressure gradients (FPG); and the opposite is true at adverse pressure gradients. boundary layer turbulence gas turbines blades laminar to turbulent transitions heat transfer Ensemble...

...Xue Feng Zhang; Maria Vera; Howard Hodson; Neil Harvey An experimental study was conducted to improve the performance of an aft-loaded ultra-high-lift low-pressure turbine blade known as U2 at low Reynolds numbers. This was achieved by manipulation of the laminar-turbulent transition process...