PERC

Biologically inspired underwater vehicle characterization

A 15 foot tall, 26 foot diameter (60,000 gallon) testing tank provides a controlled environment to test and characterize small underwater vehicles. The tank is also used to field test and verify the design underwater sensors such as an acoustic modem and a lateral line inspired flow sensor.
An additional rectangular tank is used to experimentally characterize design iterations of the Vortex Ring Thursters (VRTs). The thruster tank is made of clear acrylic which allows for visual access and Particle image velocimetry (PIV) to analyze the fluid motion during thruster actuation.

Micro Aerial Vehicle characterization

The Prototunnel is a low speed open circuit/closed jet wind tunnel uniquely suited for experimental investigations of the flight conditions of Micro Aerial Vehicles (MAVs), which fly in a poorly understood regime that is fundamentally different than conventional aircraft. The inherently low velocities of MAVs allow full scale model testing in the tunnel, thus exactly replicating the flow phenomena experienced by low Reynolds number fliers. Furthermore, the Prototunnel can be outfitted with an active grid gust generator which creates high wavelength (low frequency) turbulence with length scales on the same order as the characteristic dimensions of the MAV. Models are dynamically actuated using the Model Positioning System (MPS), designed and built by the group to permit coupled four degree-of-freedom motion which mimics the highly maneuverable flight of MAVs. Utilization of six-component force balance data, Particle Image Velocimetry (PIV), smokewire flow visualization and hotwire anemometry allows our researchers to develop a comprehensive understanding of the complex, interactive flow associated with these versatile aircraft and to use this knowledge to improve the design and control of MAVs for use in sensor networking. The below video shows the gust generator and the model positioning system making a pitch manuever of a MAV.

Laser Induced Fluoresence

LIF uses a fluorescent dye (typically Rhodamine B) which is excited by laser light and emits light energy at a wavelength different from that of the laser. This technique may be used for several purposes. For example, LIF provides high-contrast flow visualizations and has the ability to tag the flow within a certain plane when a laser light sheet is used (PLIF). Another use is temperature field measurement whereby a dye that has a temperature-dependent fluorescence is used to indicate local temperatures in the fluid.

Laser Doppler Velocimetry system

LDV is a non-intrusive, point-wise velocity measurement. The main components of the system are a 6 W continuous wave Argon laser, a mulit-color (wavelength) beam splitter, and transmitting/receiving optics. LDV is often used for turbulence measurements and can also provide accurate measurements of very high-speed flows.


Bio Fluid Dynamics and Robotics (BFDR) Laboratory

Particle Image Velocimetry

The Prototunnel is a low speed open circuit/closed jet wind tunnPIV is a non-intrusive technique used to measure velocity fields. We have several specialized pieces of equipment that allow us to perform experiments for a wide range of applications.

Conventional PIV

This system consists of a 200 mJ pulsed Nd:YAG laser and a 4 Mpx CCD camera and is ideal for measuring predominantly 2-D, low-speed flows with high spatial resolution. The spatial resolution of the camera and high pulse energy of the laser is a combination which allows for large flow fields to be measured, such as the full wake structure behind a moving object (e.g. MAVs, swimming/flying animals).

High-speed Stereoscopic PIV

This system consists of a 20 mJ Nd:YLF and two 1 Mpx CMOS cameras and is well-suited to measure time-dependent, inherently 3-D flows. The measurements yield planes of 3-D velocity vectors and can be acquired at a rate up to 2,000 frames per second. Such acquisition rates are required to fully resolve high frequency vortex shedding and synthetic jets.

Micro-PIV

This system uses the same equipment as conventional PIV, except the camera is coupled to a microscope objective to provide the large magnifications needed to measure flows within the physically small regions of interest. We also have built a lens tube to accommodate micro-flows that require a horizontal imaging axis.

Water Tunnel

This Loligo Systems recirculating water tunnel has a test section that is 1.5 m long and with a 25 cm x 25 cm cross section, and is constructed from optically-clear acrylic to allow the use of experimental imaging techniques such as PIV. The variable speed motor is capable of creating uniform freestream speeds up to 2 m/s. The water tunnel is also bio-compatible and has a surrounding temperature bath so that live aquatic animals (e.g. fish, squid) may be safely used in testing. The water tunnel is equipped with a respirometer for the measurement of oxygen content in the water. This allows the determination of oxygen consumption rates of swimming animals and, hence, metabolic efficiencies.

Squid care and testing

The squid care and testing facility provides a controlled environment for the study of cephalopod locomotion. The facility consists of 2 parts; the housing section is a 700 gallon tank which maintains temperature and chemical levels with high accuracy. The testing system is a swim tunnel with a 25x25x150 cm test section, with both PIV and respirometry measurement capabilities, and uses treated water from the housing tank. Results from visualization experiments provide researchers with new insight to how these amazing creatures propel themselves through the water. With this knowledge, researchers are then able to design and characterize a new generation of thruster for underwater vehicles. The movie below shows a pair of cuttle fish swimming around the squid care and testing facility.

Infrared Thermography

An IRE-640 mid wave cooled high speed infrared camera is available for non-invasive temperature measurement, or infrared thermography. This camera has a resolution of 640x512 pixels that captures images at a frame rate up to 120 fps while maintaing a thermal resolution of less than 20 mK. The camera is equipped with a 50 mm lens, 25 mm lens, and extender ring along with Dstar camera control and image processing software. The high pixel count and frame rate give this camera excellent spatial and temporal resolution for temperature measurement that is crucial for characterizing heat transfer phenomena.

Dissection microscope

This piece of equipment is a Zeiss SteREO Discovery V8 stereomicropscope and is designed for 3-D observation of small objects at simultaneous magnification (1x to 8x). This microscope is fitted with a camera port to allow for photographic imaging of specimens. This type of microscope uses reflected illumination, as opposed to transmitted light, which makes it ideal for thicker specimens (e.g. some tissue samples) and those where the surface topology is of interest.


Electronics Lab

Mechatronics design and fabrication

A small electronics lab allows for fabrication and modification of electrical components related to the research group's unmanned vehicles. The lab is equipped with equipment necessary to design, populate and debug complex printed circuit board designs. A 4-axis CNC milling machine provides the capabilities necessary for fabrication of the simple to highly complex, high quality components required by the research group.


Applied and Theoretical Multiphysics (ATM) Laboratory

Computational resources

We have two main computational servers with a total of 60 CPUs and 192Gb of RAM for large scale computations. Additionally, we have about 15 quadcore desktops for code developement and testing, data processing, visualization, and everyday work.