COBEM99

SR13 Mecânica dos Fluidos

Title:

PERFORMANCE OF LOW-REYNOLDS K-E MODELS TO PREDICT FLOW THROUGH CURVILINEAR OBSTRUCTION

Summary :

AT THE PRESENT WORK THE PERFORMANCE OF THREE DIFFERENT LOW REYNOLDS NUMBER K-E TURBULENCE MODELS, FOR THE PREDICTION OF FLOWS IN THE PRESENCE OF SEPARATION AND REATTACHMENT, IS INVESTIGATED. THE GEOMETRY OF INTEREST CONSIST OF A DUCT WITH CURVILINEAR OBSTRUCTION DESCRIBED BY A COSINE CURVE. THE OBJECTIVE OF THE ANALYSIS IS TO VERIFY IF THE MODELS SELECTED ARE CAPABLE OF CAPTURING THE RECIRCULATION AREAS AND PRESSURE RECOVERY AFTER THE OBSTRUCTION, FUNDAMENTALS FOR THE EVALUATION OF THE DISTRIBUTION OF TENSIONS. THE FIELDS OF VELOCITY, TURBULENT KINETIC ENERGY AND DISSIPATION RATE WERE OBTAINED BY THE DIFFERENT MODELS. COMPARISON WITH NUMERIC AND EXPERIMENTAL DATA FOUND IN THE LITERATURE IS PERFORMED, SEEKING TO IDENTIFY WHICH MODEL IS MORE ADAPTED FOR THOSE TYPE OF FLOWS. THE NUMERIC DETERMINATION OF THE FLUID FLOWS WAS ACCOMPLISHED BY A FINITE VOLUME METHOD WITH NON-ORTHOGONAL CURVILINEAR COORDINATES, WHICH ADAPTS TO THE GEOMETRY. THE COUNTERVARIANTS VELOCITY COMPONENTS WERE EMPLOYED AS INDEPENDENT VARIABLES IN THE MOMENTUM CONSERVATION EQUATION AND THE VELOCITY-PRESSURE COUPLING WAS SOLVED BY THE SIMPLEC ALGORITHM. AMONG ALL TESTED MODELS, NONE WAS ABLE TO REPRODUCE EXACTLY THE EXPERIMENTAL DATA. SATISFACTORY MEAN VELOCITY AND PRESSURE DISTRIBUTION WERE OBTAINED, HOWEVER, POOR RESULTS WERE ENCOUNTERED FOR THE TURBULENT QUANTITIES.

Author :

Nieckele, Angela Ourivio
Zevallos, Gladys N.

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