Encyclopaedia Index

### TITLE : Delta-winglets behind a cylinder

BY : Dr S V Zhubrin, CHAM Ltd

DATE : November, 2000 / February 2019

FOR : Demonstration case for V3.3.1 / PHOENICS 2019

### 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.

### COMPUTATIONAL DETAILS

### 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 :

- Geometry considered
- Streamlines showing the vortex
- Streamlines showing the vortex (Animation)
- Secondary flow further downstream
- Velocities at the bottom plane
- Velocities at a higher plane
- Velocities at 0.8H plane
- Pressure distributions
- Turbulent viscosity distributions
- Turbulence energy distributions
- Turbulence length scale distributions

### THE IMPLEMENTATION

All model settings have been made in VR-Editor of PHOENICS 2019

The relevant Q1 file can be inspectedby clicking
here.

svz