ETD

Archivio digitale delle tesi discusse presso l'Università di Pisa

Tesi etd-11052018-201330


Tipo di tesi
Tesi di laurea magistrale
Autore
PIERONI, ANDREA
URN
etd-11052018-201330
Titolo
CFD Analysis of NASA Common Research Model: Numerical Model Validation and Comparison with a Curved Planform Shape
Dipartimento
INGEGNERIA CIVILE E INDUSTRIALE
Corso di studi
INGEGNERIA AEROSPAZIALE
Relatori
relatore Prof. Chiarelli, Mario Rosario
Parole chiave
  • Fluent
  • Curved wing
  • Curved Planform
  • Comparison
  • CFD
  • CATIA
  • ICEM
  • NASA Common Research Model
Data inizio appello
27/11/2018
Consultabilità
Completa
Riassunto
Transonic aerodynamic analyses of a high aspect ratio wing-body model with curved planform are shown in this work.
The NASA Common Research Model, representative of a modern transport aircraft, is selected as reference geometry (Chapter 1).
Different geometries are designed by shifting back the swept wing airfoils of the CRM between kink and tip stations, thus maintaining the same geometric characteristics, apart from the planform shape (Ch. 2).
A structured hexa_mesh is modeled in ANSYS ICEM CFD by a top-down blocking strategy. An automated procedure is developed to guarantee grid association to any curved wing shape in a wide range of configurations. By changing few variables, the mesh topology is quickly and accurately controlled through CAD implementation of proper features. Additionally, a full parametric script, enables manipulation of nodes density distribution in each region of the fluid domain. This process allows to save human resources and times needed for in series mesh generation; at the same time it ensures very similar grids for different geometries, granting similarity in discretization errors of CFD analyses (Ch. 3).
CRM experimental data of National Transonic Facility is exploited for validation of the CFD analysis, performed in ANSYS FLUENT (Ch. 4).
After the simulation of three distinct planforms at varying angles of attack and Reynolds numbers, the best geometry is selected by analyzing numerical results. The chosen curved planform wing-body model is compared to the original CRM with swept wing (Ch. 5).
Analyses are performed for varying angles of attack α and Mach numbers M=0.8, 0.85, 0.875, 0.9. The curved configuration shows a wave drag reduction leading to a higher MAch Drag Divergence. As the curved wing produces less lift at equal α, the fuselage drag component negatively affects the comparison at fixed CL. After the wing contribution is isolated, the curved wing shows comparable aerodynamic efficiencies in a 0.3% range at M=0.8 and 0.85 for CL=0.5, but slightly higher (1%) maximum L/D at smaller CL values. Significantly better behavior is shown for M=0.875 and 0.9, confirming the MDD increase.