Ms. Sarah J. Haack Profile

Sarah J. Haack

SPIE Involvement:

Author

Publications (2)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 18 April 2007 Paper

Comparison of active flow control devices on bluff body shapes

Sarah Haack, Alison Flatau

Proceedings Volume 6523, 65230A (2007) https://doi.org/10.1117/12.717008

KEYWORDS: Actuators, Plasma, Electrodes, Control systems, Dielectrics, Copper, Particles, Amplifiers, Electrons, Temperature metrology

Read Abstract +

Results from experimental studies on the performance of plasma and synthetic jet actuators for active control of flow over a circular cylinder in subcritical flow conditions ranging from a Reynolds Number of 2.5 x 10⁴ to 7.3x10⁴ are presented. The experiments were conducted at the NASA Langley Research Center in the 20" x 28" Shear Flow Wind Tunnel and the results provide an indication of the effectiveness of, as well as the similarities and differences between these two active flow control (AFC) methods for reducing pressure drag on a bluff body shape. Flows over a cylinder are well understood and in particular flow separation characteristics for cylinders are well documented both experimentally and theoretically. The effect of the flow control devices is quantified by measuring the pressure distribution around the bluff bodies using a multi-port piezoelectric pressure scanner and integrating the distribution for drag analysis. This comparison consists of operating the two types of actuators in the same range of Reynolds Numbers (Re) over the cylinder and for the same actuator angular positions on the cylinder. The applied voltages and frequencies to the actuators varies based on the individual actuator operating conditions. At low Re, the plasma actuators have a strong effect on the pressure distribution reducing the drag up to 32% relative to the drag with no actuators on the surface. The synthetic jet reduces drag up to 25% but with lower voltage and frequency. For both actuator cases, the actuator is the most effective 5° to 10° upstream of the baseline separation point.

Proceedings Article | 21 July 2004 Paper

Design and modeling of a single-crystal iron-gallium large magnetostrictive dynamic research transducer

Luke Twarek, Sarah Haack, Alison Flatau

Proceedings Volume 5387, (2004) https://doi.org/10.1117/12.540229

KEYWORDS: Transducers, Magnetism, Iron, Magnetostrictive materials, Gallium, Metals, Terbium, Sensors, Amplifiers, Dysprosium

Read Abstract +

Alloys of iron and non-magnetic gallium (of the form Fe1-xGax where x ranges from 13 to 30) exhibit large magnetostrictions of over 300 ppm at room temperature that are produced by saturation magnetic fields of approximately 600 Oe. While not producing magnetostrictions of the degree achievable with giant magnetostrictives, large magnetostrictive alloys of iron and gallium, called Galfenol, have much more desirable mechanical characteristics, such as non-brittleness and in-plane auxetic behavior. Additionally, Galfenol requires a much smaller saturation magnetic field than the giant magnetostrictives Terfenol and Terfenol-D (alloys of Iron and non-metallic Terbium and Dysprosium). Beginning from the body of knowledge gained from Terfenol and Terfenol-D dynamic research transducer designs is a good starting point for designing a Galfenol dynamic research transducer. However, several modifications are being made to adapt the transducer to some of Galfenol's unique properties. Any measured value uncertainty will quickly propagate through the calculated material properties. While not completely successful at addressing all the unique aspects Galfenol in this transducer design, the data presented will assist in future design attempts.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks. You are receiving this notice because your organization may not have SPIE eBooks access.*

*Shibboleth/Open Athens users─please sign in to access your institution's subscriptions.

To obtain this item, you may purchase the complete book in print or electronic format on SPIE.org.

ORGANIZATIONAL
Sign in with credentials provided by your organization.

Organizational Username

Organizational Password

Show/Hide Password

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years