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Showing papers by "Terrence W. Simon published in 2010"


Journal ArticleDOI
TL;DR: A review of the heat transfer literature published in 2005 can be found in this article, where the authors restrict themselves to papers published in English through a peer-review process, with selected translations from journals published in other languages.

96 citations


Journal ArticleDOI
TL;DR: A review of heat transfer literature published in 2004 in English language, including some translations of foreign language papers, is presented in this paper, where papers are grouped into subject-oriented sections and further divided into sub-fields.

56 citations


Journal ArticleDOI
TL;DR: In this paper, a unit cell scale computation of laminar steady and unsteady fluid flow and heat transfer is presented for a spatially periodic array of square rods representing two-dimensional isotropic or anisotropic porous media.

43 citations


Journal ArticleDOI
TL;DR: In this paper, numerical simulations of flow and heat transfer in a serpentine heat exchanger configuration are presented to demonstrate the application of porous media techniques in heat exchange analysis, using two different approaches.

20 citations


Proceedings ArticleDOI
04 Jan 2010
TL;DR: In this paper, the force contours produced during dielectric barrier discharge on a plasma actuator were discussed. But the authors did not consider the effect of the dielectrics on the dynamics of the discharge.
Abstract: We have discussed the force contours produced during dielectric barrier discharge on a plasma actuator. There is asymmetry in the direction and magnitude of forces during cathode directed and anode directed discharges. This can be attributed to the difference in the dielectric charging characteristics during positive and negative pulses. Accurate modeling of surface processes on the dielectric is essential to understanding the working of the actuator. Nomenclature n p e n n n , , = densities of electrons, positive ions, and negative ions n p e D D D , , = species diffusivities n p e µ µ µ , , n p e v v v    , , = species mobility = species velocity r e e , 0

10 citations


Proceedings ArticleDOI
04 Jan 2010
TL;DR: In this paper, the behavior and characteristics of a DBD plasma actuator were investigated under different experimental conditions, with the goal of finding ways to improve and control the plasma actuators efficiency for low-pressure turbine applications.
Abstract: on airfoils 1-4 . A plasma actuator is a dielectric barrier discharge (DBD) device that can be used to selectively add momentum to fluid flow over a surface to effect flow separation. Our research program is directed at studying the potential application of plasma actuators for improving the performance and efficiency of low-pressure turbines. In this application, plasma actuators can trigger the transition between laminar and turbulent flow, thus reducing drag and leading to an increase in the turbine’s efficiency. The study reported in this paper focuses on the behavior and characteristics of the plasma actuator itself and its operation under different experimental conditions, with the goal of finding ways to improve and control the plasma actuator’s efficiency for low-pressure turbine applications. In this work, DBD plasma actuators are studied in an experimental system that allows precise control of the discharge environment. The plasma actuator is operated in a vacuum chamber and its operation monitored by an array of diagnostic techniques. Measurements of the discharge current and voltage along with time resolved imaging of the discharge utilizing an Intensified Charge-Coupled Device (ICCD) camera provide information about the discharge characteristics. A lever-style balance scale system is used for measurement of the thrust generated by the plasma actuator. A capacitor-based technique allows for power measurements, from which the efficiency (thrust/power) of plasma actuators of varying designs can be compared. A key goal of this study is to arrive at scaling laws for plasma actuator performance as a function of the operating parameters (e.g., permittivity of the dielectric, frequency and amplitude of the applied voltage, and geometry of the plasma actuator). We expect such scaling laws to be of great value in the design of more effective plasma actuators for use in low-pressure turbines.

9 citations



Proceedings ArticleDOI
04 Jan 2010
TL;DR: In this paper, a dielectric barrier discharge plasma actuator is operated in quiescent air and in flow over a Low Pressure Turbine (LPT) airfoil at a Reynolds number of 50,000 and inlet free -stream turbulence intensity of 2.5%.
Abstract: A Dielectric Barrier Discharge plasma actuator is o perated in quiescent air and in flow over a Low Pressure Turbine (LPT) airfoil at a Reynolds number of 50,000 (based on exit velocity and suction surface length) and inlet free -stream turbulence intensity of 2.5%. Measurements of velocity and total pressure are taken with constant and intermittent operation of the actuator to study the effects of e xcitation frequency and amplitude on flow velocity, and the effects of the intermittent signa l parameters on separation control. LPT measurements are also taken with opposite and aligned actuator orientations, and downstream of the span-wise plasma discharge edge. The objectives of this paper are: a) to investigate the authority of the plasma actuator fo r control of bypass transition and separation of low Reynolds number flows in LPT airfoil geometries, b) to comment on the relationship between separation control and frequency of disturbance, and c) to examine the role of three-dimensional vortical disturbances on separation control. Control is demonstrated with the actuator imparting momentum opposite to the flow direction, showing that it is possible to use disturbances alo ne to destabilize the flow and effect transition. No frequencies of strong influence are found over the range tested, indicating that a broad band of effective frequencies exists. Edge effects are found to considerably enhance separation control.

2 citations