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Different Incidence Angles (different + incidence_angle)
Selected AbstractsEffect of incidence angle with wake passing on a film cooled leading edge: A numerical studyINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2010F. Montomoli Abstract This work presents the numerical study of a film-cooled blade under the influence of wake passing at different incidence angles. The film cooling technology has been proven to be effective to increase the blade life of first turbine stages. However, the leading edge is affected by an high heat transfer rate and cooling this region is difficult. Moreover, separated regions downstream the coolant injection increases the local heat transfer coefficient and can have a detrimental effect in terms of airfoil life. This work analyses how the flow field is affected by the wake passing at different incidence angles (,5, 0, 5) and the impact on heat transfer coefficient. The test case is a linear cascade with two rows of cylindrical holes at the leading edge. Two different holes arrangements are compared in terms of film cooling structures, namely AGTB-B1 and AGTB-B2 with 0 and 45, spanwise inclination. The numerical results show a good agreement with the experiments. A deeper investigation is carried out on AGTB-B1. The results obtained show that the wake passing and the incidence angle have a strong effect on coolant jets. In particular, there is a significative impact on coolant redistribution near the leading edge. The wake passing has a stronger effect on pressure side, mainly at negative incidence. The predictive approach is based on an U-RANS in-house CFD solver using a conventional two-equations closure. In order to avoid extra turbulence production, critical in the leading edge region, the turbulence model incorporates an extra algebraic equation that enforces a realizability constraint. The unsteady formulation is based on a dual time stepping approach with a sliding plane between the moving bars and the cascade. Copyright © 2009 John Wiley & Sons, Ltd. [source] A two-step Taylor-characteristic-based Galerkin method for incompressible flows and its application to flow over triangular cylinder with different incidence anglesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 11 2010Yan Bao Abstract An alternative characteristic-based scheme, the two-step Taylor-characteristic-based Galerkin method is developed based on the introduction of multi-step temporal Taylor series expansion up to second order along the characteristic of the momentum equation. Contrary to the classical characteristic-based split (CBS) method, the current characteristic-based method does not require splitting the momentum equation, and segregate the calculation of the pressure from that of the velocity by using the momentum,pressure Poisson equation method. Some benchmark problems are used to examine the effectiveness of the proposed algorithm and to compare with the original CBS method, and the results show that the proposed method has preferable accuracy with less numerical dissipation. We further applied the method to the numerical simulation of flow around equilateral triangular cylinder with different incidence angles in free stream. In this numerical investigation, the flow simulations are carried out in the low Reynolds number range. Instantaneous streamlines around the cylinder are used as a means to visualize the wake region behind, and they clearly show the flow pattern around the cylinder in time. The influence of incidence angle on flow characteristic parameters such as Strouhal number, Drag and Lift coefficients are discussed quantitatively. Copyright © 2009 John Wiley & Sons, Ltd. [source] A modified expression for determining the wall thickness of monolithic half-wave radomesMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2001S. Sunil Abstract A comparison of the wall thickness for a monolithic half-wave radome at different incidence angles is made by considering the loss tangent of the material used. It is seen that, for large incidence angles and for moderately low-loss radome materials, the computed wall thickness is different from the values obtained by neglecting the loss tangent of the material. The above context seems to be important, particularly for variable thickness radomes for aerospace applications where the thickness from nose to base varies with the angle of incidence and angle of polarization so as to achieve the optimum design of the radome. An expression for computing the wall thickness is given which is valid for both moderately lossy and very low-loss radome materials. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 350,352, 2001. [source] | ||||||||||