Encyclopaedia Index

### TITLE : Delta-winglets behind a cylinder

BY : Dr S V Zhubrin, CHAM Ltd

DATE : November, 2000

FOR : Demonstration case for V3.3.1

### INTRODUCTION

Longitudinal vortices generated by Delta Winglet Pairs, DWP, at the angles of attack spiral the flow around the main flow direction and thereby increase mixing and heat transfer. A "cut-off" technique, PARSOL, for the representation of the complex shapes on the cartesian grid is used here aimed at the demonstration of the method for the simulation of turbulent 3D flow over a cylinder with attached DWP.

### PHYSICAL SITUATION

The demonstration case considered consists of a half of cylinder placed in an air flow within a rectangular duct. The delta-winglet is mounted on the wall behind a cylinder. The position of the wingle tip is a half of cylinder diameter relative to the center of cylinder. The right triangle winglet with a hight equal to the duct width has an angle of attack of 45 degree.

The pressure difference between the pressure and the suction sides of the winglet is anticipated to generate longitudinal vortex which supresses the flow separation on cylinder and develops well pronounced secondary flow.

The task is to calculate the flow and pressure fields along with all related field distributions.

### Conservation equations

The independent variables of the problem are the three components of cartesian coordinate system, namely X, Y and Z.

The main dependent (solved for) variables are:

• Pressure, P1
• Three components of velocity, U1, V1, W1
• Turbulence energy and its dissipation rate, KE, EP

### THE RESULTS

The plots show the distribution of velocities, pressure and other related fields within the flow.

Pictures are as follows :

### THE IMPLEMENTATION

All model settings have been made in VR-Editor of PHOENICS 3.3.1

The relevant Q1 file can be inspectedby clicking here.

svz