Embedded Files
MATLAB BOLENDER/BERMAN AND WANG AERODYNAMIC MATHEMATICAL MODEL
%Plotting Dependece of eta t vs Time
%Parameters
thetam= 0:pi/2 % degrees
f=0:122 % in HZ
etam= 0:pi %deg
Ceta=0:0.1
phieta=-pi:pi %degrees
etanot=etam-pi:pi-etam %degrees
t=[0:.1:1]
eta = (etam/tanh(Ceta))*tanh(Ceta*sin(2*pi*f*t + phieta))+ etanot
plot(t,eta)
%Berman and Wang/Boledner ; Plotting F Vs t/T
%Parameters
c=4.02 % in mm
R= 13.2 % in mm
r=[0:1: R];
t=[0:1:10]
Mwing= 0.4 % BB01 mg
rhof= 1.29 % kg/m^3 density of surrounding fluid
N=1
thetam=12.3 % degrees
f=122 % in HZ
thetadeg= -102.2 %degrees
thetanot= 1.83
etam=87 %deg
Ceta=0.1
phieta=-91.8 %degrees
etanot=-90 %degrees
tdependence=[0:.1:1]
phim=[
%Equations of Motion
%C=[0:.1:5]
T= 1/f
H= t/T
C = ((4*c)/pi)*sqrt(1-(r.^2/R.^2)); % C= c(r)
M12= (pi/4)*rhof*C^2
theta=thetam*cos(2(pi)N*f*t+ thetadeg) +thetanot
thetadot=f*N*thetam*thetanot*sin(2*pi*f*N*t+thetadeg)
eta = (etam/tanh(Ceta))*tanh(Ceta*sin(2*pi*f*tdependence + phieta))+ etanot
phi= phim
phi'=
Vy'=r*(thetadot*cos(eta)-phi'*cos(theta)*sin(eta))
%Plots
plot(C,r)
plot(F,H)
plot(eta,tdependence)
Problem Fixed
http://www.cfd-online.com/Forums/ansys/77619-fluent-warning.html
The geometry
https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Airfoil+-+Problem+Specification
http://overtheairwaves.com/vol5-8m.html
http://www.mae.ncsu.edu/apa/kiran_ramesh/Publications_files/Kiran_Orlando_012011.pdf
http://skemman.is/stream/get/1946/8934/24323/1/MS_ritgerd.pdf
http://seniord.aere.iastate.edu/reports/FLAPFLAP-2-SP10-groupreport-review-report.pdf
The purpose of using computational fluid dynamics (CFD) to model the
airflow around a hovering wing was to visualize how lift could be generated
using a flapping, figure eight pattern.The model used for CFD analysis was a 2D vertical flat plate (representing
the tip of a wing). First, a 2D mesh needed to be generated in ANSYS ICEM
CFD. This mesh was then imported into fluent. Boundary conditions were
applied so that the edges of the mesh were considered pressure outlets and
the flat plate was considered a wall. Air was used as the fluid volume. Next,
a dynamic mesh needed to be implemented. This dynamic mesh would use a
user defined function (UDF) written in C to describe the motion of the plate
in a figure eight pattern. Using a transient time solver, a solution could be
found and made into an animation to show the resultant flow velocity and
direction from the figure eight movement.
At the time of the writing of this report, the CFD analysis has only
progressed as far as the generation of a 2D mesh and the application of
boundary conditions. While solutions have been demonstrated for a rotating
or translating flat plate, a UDF has not yet been written to describe the
figure eight motion.
There were many challenges that arose during the attempts to create a
useful CFD simulation. First of all, the basics of Fluent had to be learned.
Few resources were available, other than those online, for learning this
software. In addition, few tutorials covered a 2D mesh generation. Previous
knowledge of 2D mesh generation involved the use of Gambit. Currently,
ISU no longer has a license for Gambit and therefore the learning of ANSYS
ICEM CFD was also necessary. One major challenge was the implementation
of the UDF. During attempts to complete a tutorial on dynamic meshes, an
error (open_udf_library: Access is denied.) was consistently received. No
help for this particular error was available online and a technical support
request was submitted in the ANSYS Customer Portal. This problem was
eventually resolved and the tutorial on dynamic meshes was completed
successfully. The next challenge will be writing the specific UDF for the figure
eight motion. While the equation to draw a figure eight is not difficult,
converting it to C code compatible with Fluent's dynamic mesh (and with
limited C writing knowledge in the first place) could be a challenge.
Relevant Flapping papers:
[2] ANSYS Workbench Tutorial – Boundary Layer on a Flat Plate
http://www.mne.psu.edu/cimbala/Learning/ANSYS/Workbench_Tutorial_Boundary_Layer.pdf
[3] Evaluation of Ground Effect on the Drag on an HPV Fairing Using CFD
http://scholarworks.csun.edu/bitstream/handle/10211.2/1173/Final.pdf?sequence=1
Chapter 4: Baseline Solution and Calibration of FLUENT………….…….………….....75
4.1. FLUENT Calibration Using Flat Plate………………………………………......76
Page updated
Google Sites
Report abuse