Vortex Generator Mesher

The PGL.components.vgmesher.VGMesher class generates a 3D surface mesh on an extruded airfoil section fitted with a delta-shaped vortex generator. You can specify the VG’s chordwise location, length, height, angle, intra- and inter-spacing, which is illustrated in the figure below.

_images/vg_schematic.png

While the figure shows several VG pairs, we normally only simulate a single VG vane, indicated in dark grey, and apply symmetry boundary conditions on the lateral boundaries, which is equivalent to an infinite array of VGs.

In PGL.examples.vg_example.py you can find an example that generates a VG on an FFA-W3-301 airfoil:


from PGL.components.vgmesher import VGMesher

v=VGMesher()

# airfoil shape
v.airfoil_filename = 'data/ffaw3301.dat'

# VG geometry
v.h = 0.01
v.l = 0.02
v.w = 0.00015
v.delta1 = 0.045
v.delta2 = 0.04
v.beta = 15.

# chordwise position of VG
v.xc_vg = 0.2

# base plate length and radius of fillet between plate and VG
v.l_base = 3.
v.dr_base = 0.06

# number of vertices on airfoi in the
# chordwise direction (excluding the VG)
v.nte = 7
v.ni = 257

# distribution of cells on VG
v.ni_base = 7
v.ni_cap = 50
v.ni_edge = 7
v.ni_mid = 20

# parameters controlling connector placement
v.fLE0 = 0.3
v.fLE1 = 0.0
v.fTE0 = 0.4
v.fTE1 = 0.4
v.fLEcap = 0.6
v.CPb0 = 0.45
v.wCap = .45

# run it
v.update()

# split blocks to have size 33
v.domain.split_blocks(33)

# write domain to a plot3d file
v.domain.write_plot3d('vg.xyz')

# write the domain to HypGrid2D x2d format
from PGL.main.domain import write_x2d
v.domain.get_minmax()
# the zmin / zmax arguments sets the BCs on lateral edges to 103
write_x2d(v.domain, zmin=v.domain.zmin+1.e-4, zmax=v.domain.zmax-1.e-4)

In addition to the parameters described above, you also need to specify the number of points on the surface of the airfoil in the chordwise direction, as well as the number of points on the blunt trailing edge. The remaining parameters control the placement of connectors on the VG unit.

The VGMesher class calls the PGL.components.vgunit.VGUnit class which generates a VG unit with a normalized height of 1, and the VG leading edge at (0, 0, 0). The VGMesher class takes care of scaling, placing and projecting the VG unit onto the airfoil at the specified chordwise position xc_vg.

_images/vgunit.png
_images/vgairfoil.png