TY - JOUR
TI - LOCAL HEAT TRANSFER DISTRIBUTIONS NEAR A SHARP 180° TURN OF A TWO-PASS SMOOTH SQUARE CHANNEL USING A TRANSIENT LIQUID CRYSTAL IMAGE TECHNIQUE
AU - Ekkad, Srinath
AU - Han, Je-Chin
T2 - Journal of Flow Visualization and Image Processing
AB - Local heat transfer distributions are presented near a sharp 180° turn of a two-pass smooth square channel using a transient technique and encapsulated liquid crystal coating. Detailed distributions of the local Nusselt numbers are given for three flow Reynolds numbers of 10,000, 25,000, and 50,000. Results show that the Nusselt numbers are much higher in the region immediately downstream of the turn compared with upstream values for all three Reynolds numbers. The regional averaged results are compared with published heat transfer data.
DA - 1995///
PY - 1995///
DO - 10.1615/jflowvisimageproc.v2.i3.80
VL - 2
IS - 3
SP - 285-297
J2 - J Flow Vis Image Proc
LA - en
OP -
SN - 1065-3090
UR - http://dx.doi.org/10.1615/jflowvisimageproc.v2.i3.80
DB - Crossref
ER -
TY - CONF
TI - Local heat transfer coefficient and film effectiveness distributions on a cylindrical leading edge model using a transient liquid crystal image method
AU - Ekkad, Srinath V.
AU - Du, Hui
AU - Han, Je-Chin
C2 - 1995///
C3 - American Society of Mechanical Engineers (Paper)
DA - 1995///
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0029491932&partnerID=MN8TOARS
ER -
TY - CONF
TI - Heat transfer coefficients over a flat surface with air and CO2 injection through compound angle holes using a transient liquid crystal image method
AU - Ekkad, S.V.
AU - Zapata, D.
AU - Han, J.-C.
AB - This paper presents the detailed heat transfer coefficients over a flat surface with one row of injection holes inclined streamwise at 35° for three blowing ratios (M=0.5–2.0). Three compound angles of 0°, 45°, and 90° with air (D.R.=0.98) and CO2 (D.R.=1.46) as coolants were tested at an elevated free-stream turbulence condition (Tu≈8.5%). The experimental technique involves a liquid crystal coating on the test surface. Two related transient tests obtained detailed heat transfer coefficients and film effectiveness distributions. Heat transfer coefficients increase with increasing blowing ratio for a constant density ratio but decrease with increasing density ratio for a constant blowing ratio. Heat transfer coefficients increase for both coolants over the test surface as the compound angle increases from 0° to 90°. The detailed heat transfer coefficients obtained using the transient liquid crystal technique, particularly in the near hole region, will provide a better understanding of the film cooling process in gas turbine components.
C2 - 1995///
C3 - Proceedings of the ASME Turbo Expo
DA - 1995///
DO - 10.1115/95-GT-010
VL - 4
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84976874954&partnerID=MN8TOARS
ER -
TY - CONF
TI - Film effectiveness over a flat surface with air and CO2 injection through compound angle holes using a transient liquid crystal image method
AU - Ekkad, S.V.
AU - Zapata, D.
AU - Han, J.-C.
AB - This paper presents detailed film effectiveness distributions over a flat surface with one row of injection holes inclined streamwise at 35° for three blowing ratios (M=0.5, 1.0, 2.0). Three compound angles of 0°, 45°, and 90° with air (D.R.=0.98) and CO2 (D.R.=1.46) as coolants are tested at an elevated free-stream turbulence condition (Tu≈8.5%). A transient liquid crystal technique is used to measure local heat transfer coefficients and film effectiveness. Detailed film effectiveness results are presented near and around film injection holes. Compound angle injection provides higher film effectiveness than simple angle injection for both coolants. Higher density injectant produces higher effectiveness for simple injection. However, lower density coolant produces higher effectiveness for a large compound angle of 90°. The detailed film effectiveness obtained using the transient liquid crystal technique, particularly in the near hole region, provided a better understanding of the film cooling process in gas turbine components.
C2 - 1995///
C3 - Proceedings of the ASME Turbo Expo
DA - 1995///
DO - 10.1115/95-GT-011
VL - 4
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84976878628&partnerID=MN8TOARS
ER -
TY - JOUR
TI - Large-scale crystal plasticity computations of microstructural failure modes
AU - Zikry, M.A.
AU - Kao, M.
T2 - Computing Systems in Engineering
AB - Abstract A computational scheme is introduced for the integration of rate-dependent multiple-slip crystal plasticity constitutive relations. Fundamental issues of accuracy, stability, and stiffness that are intrinsically related to the evolution of microstructural failure modes in metallic crystals are addressed. An adaptive finite-element methodology is introduced to classify these characteristics. A nonlinear initial value system is derived to update the plastic deformation-rate tensor. An explicit method is used in non-stiff domains, where accuracy is required. If a time-step reduction is due to stability, a harbinger of numerical stiffness, the algorithm is automatically switched to an A-stable method. A stiffness ratio is defined to measure the eigenvalue dispersion of the system. The adaptability of the proposed algorithm for the solution of a class of inelastic constitutive relations is illustrated by investigating the influence of high angle grain boundary orientations on failure in face-centered cubic (f.c.c.) bicrystals. The effects of grain boundary misorientation, dislocation densities, strain hardening, and geometrical softening on failure evolution are investigated. This study underscores the importance of understanding the origin of numerical instabilities, such that these instabilities are not mistaken for inherent material instabilities.
DA - 1995///
PY - 1995///
DO - 10.1016/0956-0521(95)00024-T
VL - 6
IS - 3
SP - 225-240
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0007616957&partnerID=MN8TOARS
ER -
TY - CONF
TI - Microstructural failure mechanisms in crystalline materials
AU - Zikry, M.A.
AU - Kao, M.
C2 - 1995///
C3 - American Society of Mechanical Engineers, Applied Mechanics Division, AMD
DA - 1995///
VL - 200
SP - 143-163
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0028994195&partnerID=MN8TOARS
ER -
TY - CONF
TI - Grain-boundary effects and failure mechanisms in crystalline materials
AU - Zikry, M.A.
AU - Kao, M.
C2 - 1995///
C3 - American Society of Mechanical Engineers, Applied Mechanics Division, AMD
DA - 1995///
VL - 212
SP - 107-128
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0029427840&partnerID=MN8TOARS
ER -
TY - JOUR
TI - A New Prototype of a pineapple peeling machine
AU - Ngaile, Gracious
AU - Mshana, J.
AU - Sigh, A.
T2 - Uhandisi Journal
DA - 1995/12//
PY - 1995/12//
VL - 19
IS - 2
SP - 117–132
ER -
TY - CONF
TI - Determining Elastic Behavior of Composites by the Boundary Element Method
AU - Eischen, J.W.
AU - Torquato, S.
T2 - Fourth Pan American Congress of Applied Mechanics
C2 - 1995///
C3 - Proceedings of the Fourth Pan American Congress of Applied Mechanics
CY - Buenos Aires, Argentina
DA - 1995///
PY - 1995///
ER -
TY - CONF
TI - On the stabilization of a class of nonholonomic systems using invariant manifold technique
AU - Reyhanoglu, M.
T2 - 1995 34th IEEE Conference on Decision and Control
AB - This paper presents an asymptotically stabilizing discontinuous feedback controller for a class of nonholonomic systems. The controller consists of two parts: the first part yields an invariant manifold on which all trajectories of the closed-loop system tend to the origin, and the latter part renders the invariant manifold attractive, while avoiding a discontinuity surface. The controller yields exponential stability so that the convergence can be chosen arbitrarily fast.
C2 - 1995/11/19/
C3 - Proceedings of 1995 34th IEEE Conference on Decision and Control
CY - New Orleans, LA
DA - 1995/11/19/
PY - 1995/12/13/
DO - 10.1109/cdc.1995.480515
PB - IEEE
SN - 0780326857
UR - http://dx.doi.org/10.1109/cdc.1995.480515
ER -
TY - JOUR
TI - Control of nonholonomic systems with extended base space dynamics
AU - Reyhanoglu, Mahmut
AU - Bloch, Anthony M.
AU - Harris Mcclamroch, N.
T2 - International Journal of Robust and Nonlinear Control
AB - Abstract This paper extends certain results in Reference 1 to a more general class of nonholonomic systems with extended base space dynamics. This extension is important in applications for which control actuator dynamics are significant. These nonlinear control systems are referred to as nonholonomic control systems owing to certain nonintegrability assumptions which are made. The class of systems considered in this paper are characterized by general nonlinear base space dynamics that are input‐output decouplable. Controllability results for this class of nonholonomic control systems are presented.
DA - 1995///
PY - 1995///
DO - 10.1002/rnc.4590050408
VL - 5
IS - 4
SP - 325-330
J2 - Int. J. Robust Nonlinear Control
LA - en
OP -
SN - 1049-8923 1099-1239
UR - http://dx.doi.org/10.1002/rnc.4590050408
DB - Crossref
KW - NONHOLONOMIC SYSTEMS
KW - NONLINEAR CONTROLLABILITY
ER -
TY - CHAP
TI - Fluid-Structure Interaction Using a Loose Coupling Algorithm and Adaptive Unstructured Grids
AU - Löhner, R.
AU - Yang, C.
AU - Cebral, J.
AU - Baum, J.D.
AU - Luo, H.
AU - Pelessone, D.
AU - Charman, C.
T2 - Computational fluid dynamics review 1995
PY - 1995///
SP - 755–776
PB - Wiley
SN - 9780471955894
ER -
TY - JOUR
TI - Full Field Stability Analysis of Guy-Wired Satellites
AU - Mazzoleni, A.P.
AU - Schlack, A.L.
T2 - Journal of the Astronautical Sciences
DA - 1995/1//
PY - 1995/1//
VL - 43
IS - 1
SP - 47–57
ER -
TY - JOUR
TI - Instability tests, Lyapunov's direct method, and exact stability boundaries for flexible satellites
AU - Mazzoleni, Andre P.
AU - Dobson, Ian
T2 - Journal of Guidance, Control, and Dynamics
AB - Simple tests are developed to determine instability regions in the parameter space of flexible satellites. These tests are used in conjunction with Lyapunov's direct method to obtain exact stability boundaries in parameter space in cases where Lyapunov methods give only sufficient conditions for stability. In the case of Hamiltonian systems, the tests reduce to checking the sign of the determinant of the Hessian of the Hamiltonian at a single point. The Hamiltonian assumption can be relaxed to allow the inclusion of damping terms provided these terms have no linear dependence on position. Previous studies use complete or pervasive damping assumptions to obtain exact stability boundaries, whereas the proposed methods work for no damping or the damping described earlier. Examples illustrate the usefulness of the tests.
DA - 1995/5//
PY - 1995/5//
DO - 10.2514/3.21405
VL - 18
IS - 3
SP - 426-432
J2 - Journal of Guidance, Control, and Dynamics
LA - en
OP -
SN - 0731-5090 1533-3884
UR - http://dx.doi.org/10.2514/3.21405
DB - Crossref
ER -
TY - JOUR
TI - Attitude stabilization of a rigid spacecraft using two momentum wheel actuators
AU - Krishnan, Hariharan
AU - McClamroch, N. Harris
AU - Reyhanoglu, Mahmut
T2 - Journal of Guidance, Control, and Dynamics
AB - It is well known that three momentum wheel actuators can be used to control the attitude of a rigid spacecraft and that arbitrary reorientation maneuvers of the spacecraft can be accomplished using smooth feedback. If failure of one of the momentum wheel actuators occurs, we demonstrate that two momentum wheel actuators can be used to control the attitude of a rigid spacecraft and that arbitrary reorientation maneuvers of the spacecraft can be accomplished. Although the complete spacecraft equations are not controllable, the spacecraft equations are controllable under the restriction that the total angular momentum vector of the system is zero. The spacecraft dynamics under such a restriction cannot be asymptotically stabilized to any equilibrium attitude using a timeinvariant continuous feedback control law, but discontinuous feedback control strategies are constructed that stabilize any equilibrium attitude of the spacecraft in finite time. Consequently, reorientation of the spacecraft can be accomplished using discontinuous feedback control.
DA - 1995/3//
PY - 1995/3//
DO - 10.2514/3.21378
VL - 18
IS - 2
SP - 256-263
J2 - Journal of Guidance, Control, and Dynamics
LA - en
OP -
SN - 0731-5090 1533-3884
UR - http://dx.doi.org/10.2514/3.21378
DB - Crossref
ER -
TY - JOUR
TI - The Product of Chord Lengths of a Circle
AU - Mazzoleni, Andre P.
AU - Shen, Samuel Shan-Pu
T2 - Mathematics Magazine
DA - 1995/2/1/
PY - 1995/2/1/
DO - 10.2307/2691381
VL - 68
IS - 1
SP - 59
LA - en
OP -
SN - 0025-570X
UR - http://dx.doi.org/10.2307/2691381
DB - Crossref
ER -
TY - JOUR
TI - Closest bifurcation analysis and robust stability design of flexible satellites
AU - Mazzoleni, Andre P.
AU - Dobson, Ian
T2 - Journal of Guidance, Control, and Dynamics
AB - We consider the design of a satellite to ensure robust stability in a high-dimensional parameter space. Starting with a given nominal design that is stable, we compute instabilities that are locally closest to the nominal design in the design parameter space. If these worst-case instabilities are too close, we compute a design that is sufficiently far from the worst-case instabilities and hence sufficiently robust. The methods are based on computations from bifurcation theory and are considerably simplified by our assumption of a Hamiltonian satellite, which includes spin-stabilized satellites, dual-spin-stabilized satellites, and gravity-gradient-stabilized satellites. The Hamiltonian assumption is then relaxed to allow the inclusion of damping terms. We illustrate the computations by ensuring the robust stability of a flexible dual-spin satellite with six design parameters.
DA - 1995/3//
PY - 1995/3//
DO - 10.2514/3.21388
VL - 18
IS - 2
SP - 333-339
J2 - Journal of Guidance, Control, and Dynamics
LA - en
OP -
SN - 0731-5090 1533-3884
UR - http://dx.doi.org/10.2514/3.21388
DB - Crossref
ER -
TY - PAT
TI - Three-zone rapid thermal processing system utilizing wafer edge heating means
AU - Hauser, J.
AU - Sorrell, F.
AU - Wortman, J.
C2 - 1995///
DA - 1995///
PY - 1995///
ER -
TY - PAT
TI - Apparatus and method for forming a workpiece surface into a non-rotationally symmetric shape
AU - Dow, T. A.
AU - Garrad, K. P.
AU - Moorefield, G. M.
AU - Taylor, L. W.
C2 - 1995///
DA - 1995///
PY - 1995///
ER -