A numerical method for computing three dimensional viscous supersonic flow fields about slender bodies

A numerical method is presented for the calculation of steady, three-dimensional, viscous, compressible flow fields about slender bodies at angle of attack and at supersonic speeds. Approximations are introduced in modeling the flow in the longitudinal direction. Accordingly, the flow fields calculated with the program were computed with a model that permits viscous crossflow together with inviscid axial flow. An analysis of the errors introduced by such a treatment is presented. Numerical calculations were made and compared with experimental results for an ogive-cylinder and an airplane fuselage configuration. Generally, good agreement with experiment was obtained. However, boundary layer separation and body vortex positions differed from experimental locations on the ogive-cylinder, and the shock induced by the fuselage canopy was predicted at a slightly different location

Numerical calculations of viscous compressible fluid flow over a flat plate and step geometry

Computer programs for numerical calculation of viscous compressible fluid flow over flat plat

Numerical calculation of the internal flow field in a centrifugal compressor impeller

An iterative numerical method has been developed for the calculation of steady, three-dimensional, viscous, compressible flow fields in centrifugal compressor impellers. The computer code, which embodies the method, solves the steady three dimensional, compressible Navier-Stokes equations in rotating, curvilinear coordinates. The solution takes place on blade-to-blade surfaces of revolution which move from the hub to the shroud during each iteration

Chemobrain: a critical review and causal hypothesis of link between cytokines and epigenetic reprogramming associated with chemotherapy

One consequence of modern cancer therapy is chemotherapy related cognitive dysfunction or “chemobrain”, the subjective experience of cognitive deficits at any point during or following chemotherapy. Chemobrain, a well-established clinical syndrome, has become an increasing concern because the number of long-term cancer survivors is growing dramatically. There is strong evidence that correlates changes in peripheral cytokines with the development of chemobrain in commonly used chemotherapeutic drugs for different types of cancer. However, the mechanisms by which these cytokines elicit change in the central nervous system are still unclear. In this review, we hypothesize that the administration of chemotherapy agents initiates a cascade of biological changes, with short-lived alterations in the cytokine milieu inducing persistent epigenetic alterations. These epigenetic changes lead to changes in gene expression, alterations in metabolic activity and neuronal transmission that are responsible for generating the subjective experience of cognition. This speculative but testable hypothesis should help to gain a comprehensive understanding of the mechanism underlying cognitive dysfunction in cancer patients. Such knowledge is critical to identify pharmaceutical targets with the potential to prevent and treat cancer-treatment related cognitive dysfunction and similar disorders.postprin

Development of a locally mass flux conservative computer code for calculating 3-D viscous flow in turbomachines

The VANS successive approximation numerical method was extended to the computation of three dimensional, viscous, transonic flows in turbomachines. A cross-sectional computer code, which conserves mass flux at each point of the cross-sectional surface of computation was developed. In the VANS numerical method, the cross-sectional computation follows a blade-to-blade calculation. Numerical calculations were made for an axial annular turbine cascade and a transonic, centrifugal impeller with splitter vanes. The subsonic turbine cascade computation was generated in blade-to-blade surface to evaluate the accuracy of the blade-to-blade mode of marching. Calculated blade pressures at the hub, mid, and tip radii of the cascade agreed with corresponding measurements. The transonic impeller computation was conducted to test the newly developed locally mass flux conservative cross-sectional computer code. Both blade-to-blade and cross sectional modes of calculation were implemented for this problem. A triplet point shock structure was computed in the inducer region of the impeller. In addition, time-averaged shroud static pressures generally agreed with measured shroud pressures. It is concluded that the blade-to-blade computation produces a useful engineering flow field in regions of subsonic relative flow; and cross-sectional computation, with a locally mass flux conservative continuity equation, is required to compute the shock waves in regions of supersonic relative flow

Computation of steady axisymmetric flow using a one-dimensional time-dependent method

An iterative numerical method for computing steady, three dimensional, viscous, compressible flow fields, about aerodynamic bodies was studied. In order to develop the iterative method economically, the primary emphasis was directed towards supersonic, axisymmetric flow. However, the technique readily extends to three spatial dimensions. The viscous flow field about a cone-cylinder-flare body was calculated and compared to existing experimental data. Numerical predictions of the cone boundary layer and the flow field shock wave structure agreed with corresponding measurements. A separation was calculated at the cylinder-flare junction in six iterations; however, the size of the vortex did not correspond to the measured size. It was estimated that fifty iterations would be required to properly define the vortex. It was concluded that the iteration technique is of limited value for plane two dimensional and axisymmetrix flows, but of great value for three-dimensional flows

Computation of viscous transonic flow about a lifting airfoil

The viscous transonic flow about a stationary body in free air was numerically investigated. The geometry chosen was a symmetric NACA 64A010 airfoil at a freestream Mach number of 0.8, a Reynolds number of 4 million based on chord, and angles of attack of 0 and 2 degrees. These conditions were such that, at 2 degrees incidence unsteady periodic motion was calculated along the aft portion of the airfoil and in its wake. Although no unsteady measurements were made for the NACA 64A010 airfoil at these flow conditions, interpolated steady measurements of lift, drag, and surface static pressures compared favorably with corresponding computed time-averaged lift, drag, and surface static pressures

Increased brain white matter axial diffusivity associated with fatigue, pain and hyperalgesia in Gulf War illness

Background Gulf War exposures in 1990 and 1991 have caused 25% to 30% of deployed personnel to develop a syndrome of chronic fatigue, pain, hyperalgesia, cognitive and affective dysfunction. Methods Gulf War veterans (n = 31) and sedentary veteran and civilian controls (n = 20) completed fMRI scans for diffusion tensor imaging. A combination of dolorimetry, subjective reports of pain and fatigue were correlated to white matter diffusivity properties to identify tracts associated with symptom constructs. Results Gulf War Illness subjects had significantly correlated fatigue, pain, hyperalgesia, and increased axial diffusivity in the right inferior fronto-occipital fasciculus. ROC generated thresholds and subsequent binary regression analysis predicted CMI classification based upon axial diffusivity in the right inferior fronto-occipital fasciculus. These correlates were absent for controls in dichotomous regression analysis. Conclusion The right inferior fronto-occipital fasciculus may be a potential biomarker for Gulf War Illness. This tract links cortical regions involved in fatigue, pain, emotional and reward processing, and the right ventral attention network in cognition. The axonal neuropathological mechanism(s) explaining increased axial diffusivity may account for the most prominent symptoms of Gulf War Illness

Effectiveness of land- and water-based exercise on fatigue and sleep quality in women with fibromyalgia: the al-Ándalus quasi-experimental study

Objetivo Evaluar la efectividad de 24 semanas de ejercicio en tierra y agua sobre la fatiga y la calidad del sueño en mujeres con fibromialgia , y la persistencia de los cambios 12 semanas después de la interrupción del ejercicio. Diseño Estudio cuasiexperimental. Configuración Instalaciones universitarias y asociaciones de fibromialgia. Participantes Mujeres con fibromialgia (N=250; 50,8±7,6 años). Intervenciones Los participantes fueron asignados a grupos de ejercicio en tierra (n = 83), ejercicio en agua (n = 85) o control sin ejercicio (n = 82). Los grupos de intervención participaron en un programa de ejercicio multicomponente similar durante 24 semanas. Las principales medidas Se utilizó el Inventario Multidimensional de Fatiga y el Índice de Calidad del Sueño de Pittsburgh . Resultados Los análisis por intención de tratar revelaron que, en comparación con el grupo de control, en la semana 24: (i) el grupo de ejercicio en tierra mejoró la fatiga física (diferencia de medias -0,9 unidades; intervalo de confianza del 95%: -1,7 a -0,1; d de Cohen =0,4) y (ii) el grupo de ejercicio acuático mejoró la fatiga general (-0,8; -1,4 a -0,1, d=0,4) y la calidad global del sueño (-1,6; -2,7 a -0,6, d=0,6). Además, en comparación con el grupo de ejercicio en tierra, el grupo de ejercicio en el agua mejoró la calidad global del sueño (-1,2; -2,2 a -0,1, d=0,4). En general, los cambios no se mantuvieron en la semana 36. Conclusión El ejercicio multicomponente en tierra mejoró la fatiga física, mientras que el ejercicio en el agua mejoró la fatiga general y la calidad del sueño. La magnitud de los cambios fue de pequeña a media y no se mantuvieron los beneficios después de suspender el ejercicio.Objective: To assess the effectiveness of 24 weeks of land- and water-based exercise on fatigue and sleep quality in women with fibromyalgia, and the persistence of changes 12 weeks after exercise cessation. Design: quasi-experimental study Setting: University facilities and fibromyalgia associations. Participants: Women with fibromyalgia (N=250; 50.8 ± 7.6 years old) Interventions: Participants were assigned to land-based exercise (n=83), water-based exercise (n=85) or no exercise control (n=82) groups. The intervention groups engaged in a similar multicomponent exercise program for 24 weeks. Main outcome measures: The Multidimensional Fatigue Inventory (MFI) and Pittsburgh Sleep Quality Index (PSQI) were used. Results: Intention-to-treat analyses revealed that, compared to the control group, at week 24: (i) the land-based exercise group improved physical fatigue (mean difference -0.9 units; 95% CI -1.7 to -0.1; Cohen’s d=0.4), and (ii) the water-based exercise group improved general fatigue (-0.8; -1.4 to -0.1, d=0.4), and global sleep quality (-1.6; -2.7 to -0.6, d=0.6). Additionally, compared to the land-based exercise group, the water-based exercise group improved global sleep quality (-1.2; -2.2 to -0.1, d=0.4). Changes were generally not sustained at week 36. Conclusion: Land-based multicomponent exercise improved physical fatigue, whereas water-based exercise improved general fatigue and sleep quality. The magnitude of the changes was small-to-medium and no benefits were maintained after exercise cessation