12,012 research outputs found
The spatial stability of a class of similarity solutions
The spatial stability of a class of exact similarity solutions of the Navier–Stokes equations whose longitudinal velocity is of the form xf′(y), where x is the streamwise coordinate and f′(y) is a function of the transverse, cross‐streamwise, coordinate y only, is determined. These similarity solutions correspond to the flow in an infinitely long channel or tube whose surface is either uniformly porous or moves with a velocity linear in x. Small perturbations to the streamwise velocity of the form x^λg′(y) are assumed, resulting in an eigenvalue problem for λ which is solved numerically. For the porous wall problem, it is shown that similarity solutions in which f′(y) is a monotonic function of y are spatially stable, while those that are not monotonic are spatially unstable. For the accelerating‐wall problem, the interpretation of the stability results is not unambiguous and two interpretations are offered. In one interpretation the conclusions are the same as for the porous problem—monotonic solutions are stable; the second interpretation is more restrictive in that some of the monotonic as well as the nonmonotonic solutions are unstable
Analysis of the Brinkman equation as a model for flow in porous media
The fundamental solution or Green's function for flow in porous media is determined using
Stokesian dynamics, a molecular-dynamics-like simulation method capable of describing the
motions and forces of hydrodynamically interacting particles in Stokes flow. By evaluating the
velocity disturbance caused by a source particle on field particles located throughout a
monodisperse porous medium at a given value of volume fraction of solids ø, and by
considering many such realizations of the (random) porous medium, the fundamental solution
is determined. Comparison of this fundamental solution with the Green's function of the
Brinkman equation shows that the Brinkman equation accurately describes the flow in porous
media for volume fractions below 0.05. For larger volume fractions significant differences
between the two exist, indicating that the Brinkman equation has lost detailed predictive value,
although it still describes qualitatively the behavior in moderately concentrated porous media.
At low ø where the Brinkman equation is known to be valid, the agreement between the
simulation results and the Brinkman equation demonstrates that the Stokesian dynamics
method correctly captures the screening characteristic of porous media. The simulation results
for ø ≥ 0.05 may be useful as a basis of comparison for future theoretical work
CONCEPTUAL UNDERPINNINGS OF POLICY ANALYSIS FOR RURAL DEVELOPMENT
Community/Rural/Urban Development,
Evaluation of liquid methane storage and transfer problems in supersonic aircraft
Evaluation of liquid methane storage and transfer problems for future supersonic aircraft cryogenic fuel requirement
How do we know what works? Evaluating data on the extent and impact of young people’s involvement in English health research
The case for children and young people’s involvement in health research has been well documented, but less attention has been paid to the experiences and impact of involving children and young people rather than adults. This paper explores these issues in relation to a project undertaken for the James Lind Initiative on the availability, quality and reliability of existing data on young people’s involvement in studies supported by the National Institute for Health Research (NIHR). The project found that there was no systematic way of getting reliable and comparable information about which young people are involved in health research in England, what form that involvement may have taken or the impacts of involvement. There is a need to better collate and disseminate evidence on young people’s involvement in research, using both existing systems and processes, and the possible development of new metrics and measures. Not having this information risks children and young people’s involvement continuing to develop in a piecemeal fashion. Further research is needed about how, when and where children and young people are involved in health research, and about the impact of involvement on research and on the children and young people involved
From Caution to College: The Effects on Veterans with Self- Reported Trauma Symptoms Sharing their Experiences with the Campus Community
Over 900,000 veterans are using benefits for higher education today; the vast majority of them served in the Global War on Terrorism (GWOT). Over 25% of GWOT service members that have been treated by the Veterans Affairs (VA) are reported to have symptoms of posttraumatic stress or posttraumatic stress disorder (PTS/PTSD). PTS/PTSD negatively impacts student veterans’ abilities to navigate stressful environments such as college and university settings. The Veterans Embracing Transition (VET) Connect Program at San José State University (SJSU) is designed to connect veterans with non-veterans as peer educators. Five of the 13 VET Connect peer educators (38.5%) who were interviewed reported having symptoms of PTSD. Through their service as peer educators on and off campus, these participants demonstrated signs of healthy coping effects through sharing experiences and educating non-veterans of the struggles related to military culture, service, combat, and loss. This study was conducted in collaboration with Sophia Alcala. We worked on independent research questions and observations using data derived from the same larger study simultaneously under the supervision of Dr. Klaw
Purpose and Result Clauses in Hebrews and John\u27s Epistles
Abstract unavailable
Conceptual underpinnings of policy analysis for rural development
The purpose of this paper is to provide a concise overview of the challenges associated with the breadth of the field and to suggest areas of analysis and analytic devices that would facilitate greater focus in the future
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