The Engineer
Mehul Patel is the Director of Aerodynamics Group at Cleveland-based
Orbital Research Inc. (ORI). ORI designs, develops and commercializes
custom-engineered solutions in the area of aerodynamics, MEMS, and
advanced controls for the U.S. military and industry partners. Mr.
Patel's group is active in a wide variety of efforts focused on the
development of advanced aerodynamic control systems for aircraft and
munitions.
Smart Skin for Munitions
Among the Aerodynamics Group’s most successful R&D programs
is hingeless Smart Skin for munition flight control. Working closely
with the U.S. Air Force Research Laboratory (AFRL) and the U.S. Army
Research Development and Engineering Command Armament, Research, Development
and Engineering Center (RDECOM-ARDEC), the ORI team has developed unique,
custom-engineered munition control systems using state-of-the-art flow
control actuators and algorithms that improve munition range, control,
and maneuverability.
While working on the Munition Smart Skin program, Patel’s group
discovered that traditional hinged control surfaces impose significant
limitations on munition performance. On the other hand, hingeless control
surfaces integrated with miniature flow control actuators expand overall
munition performance and payload by shaving off considerable weight from
motors traditionally used to guide fin surfaces.
This innovative, low-cost alternative for maneuvering munitions called
Munition Smart Skin contains an embedded system of miniature sensors
on a projectile's outer surface and actuators, as well as a real-time
feedback controller just below the surface. The outer layer of skin is
perforated with miniature slits. Using embedded MEMS structures, a miniature-spoiler
is pushed through the slit to induce a small physical change on the fin,
nose, or the tail, which creates a large effect on the region's flow
field. This forces an overall change in pressure distribution around
a significant portion of the surface, and pitch, roll, or yaw adjustments
can be made in real time.
Smart Skin can also be thought of as virtual shaping; meaning that
a fin or wing has the ability to change its shape and the flow field
without an actual deflection of a flap, slat, or aileron—all of
which is unseen from the exterior. This system can be transparent to
the munition navigation system and can be operated autonomously by a
ground- or air-based pilot, or by an onboard guidance system.
Simulation and Testing
To validate their research findings and test active flow control system
prototypes, ORI’s Aerodynamics Group relies heavily on low- and
high-speed wind tunnel experiments, CFD simulations, and 6-DOF flight
modeling. For CFD studies, Patel’s group uses the WIND-US code,
a 3-D Navier-Stokes flow solver developed by the merger of three CFD
codes (NASTD, NPARC, and NXAIR). Mr. Patel works closely with Dr. Alan
Cain, President of Innovative Technology Applications Company L.L.C.,
through all CFD pre- and post-processing stages.
“By combining CFD analysis with wind tunnel experiments,” Patel
explained, “we are able to reduce the total turnaround time for
feasibility studies as well as systems development. This time-saving
results in an overall lower cost for our customers, and ultimately the
U.S. taxpayer.”
Plotting and Data Visualization
Because his group frequently employs CFD simulations, Patel knew it was
imperative to find a high-quality CFD post-processing tool that was
both cost-effective and reliable. When he discovered Tecplot and coupled
it with its CFD Analyzer add-on, Patel said he has found the "perfect
solution".
“I was looking for an extensive, yet not-too-expensive, data plotting
software package, primarily for post-processing of CFD data,” Patel
said. “After learning more about the capabilities of Tecplot and
its add-on tool, CFD Analyzer, which lets user calculate variables and
extract critical information from the data set, it seemed an obvious
pick for our data processing needs.”
Patel is currently using Tecplot to look at large, 3-D data sets (typically
between 1 to 2 million grid points), which are in a multi-zone format. “Tecplot
allows me to work on a specific group of zones [by turning off other
zones] to achieve a high-level of resolution in analyzing complex data
in small regions of the computational domain,” he said. “Furthermore,
it enables me to automate complete 2- and 3-D flow analysis using macros."
The
Tecplot features most commonly used by Patel are 2-D slices, contour
plotting, streamtraces, and the CFD Analyzer add-on. “These features
are important to anyone doing CFD post-processing, and I find myself
calling upon them on a daily basis,” he said.
When asked to list Tecplot’s three greatest strengths as it relates
to his work, Patel started with the obvious. “The software’s
ease-of-use is exceptional,” he said. “It’s a breeze
to import and export files, plot data in a multitude of ways, create
custom-configurations, and make videos and animations in the file format
of my choice.”
Beyond ease-of-use, Patel cited the CFD Analyzer and Tecplot, Inc.’s “excellent” technical
support as key strengths of the product. “I haven’t had to
seek out technical assistance with any great regularity, but when I have
called Tecplot’s technical support group, I found knowledgeable
people who were truly interested in solving my problem.”
"Tecplot software has provided an incredible boost to our productivity in terms of our research output and the insights we are able to obtain." Rajat Mittal, George Washington University
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