Outflow turbulent

To avoid imposition of unrealistic exit boundary conditions in flow models Taylor et al. (1985) developed a method called traction boundary conditions . In this method starting from an initial guess, outflow condition is updated in an iterative procedure which ensures its consistency with the flow regime immediately upstream. This method is successfully applied to solve a number of turbulent flow problems. 

Proportional Element First, consider the outflow through the exit valve on the tank. If the flow through the line is turbulent, then Bernoulh s equation can be used to relate the flow rate through the valve to the pressure drop across the valve as ... 

In turbulent flow, the edge effect due to the shape of the support rod is quite significant as shown in Fig. 6. The data obtained with a support rod of equal radius agree with the theoretical prediction of Eq. (52). The point of transition with this geometry occurs at Re = 40000. However, the use of a larger radius support rod arbitrarily introduces an outflowing radial stream at the equator. The radial stream reduces the stability of the boundary layer, and the transition from laminar to turbulent flow occurs earlier at Re = 15000. Thus, the turbulent mass transfer data with the larger radius support rod deviate considerably from the theoretical prediction of Eq. (52) a least square fit of the data results in a 0.092 Re0 67 dependence for... 

ShaJSc113 as indicated by the thin solid line. This 0.67 power of Re agrees with the result of a turbulent heat transfer measurement on a rotating sphere [40], Since the flow induced by a rotating sphere is also characterized by an outflowing radial jet at the equator caused by the collosion of two opposing flow boundary layers on the sphere, the 0.67 power dependence on Re is clearly related to the radial flow stream away from the equator. 

A complete mix reactor is one with a high level of turbulence, such that the fluid is immediately and completely mixed into the reactor. The outflow concentration and the reactor concentration are equal, and the diffusion term is zero due to the gradient being zero. Figure 6.1 shows an illustration of the concept. If we make the entire reactor into our control volume, then a mass balance on the reactor gives Rate of = Flux rate - Flux rate - - Source — sink... 

Approximately 25% of all patients with hypertrophic cardiomyopathy (HCM) have latent left ventricular outflow obstruction with an intraventricular gradient (I). Pathophysiologic features are asymmetric hypertrophy of the septum and a systolic anterior movement of the anterior leaflet. Medical treatment includes betablockers, and calcium antagonists of the verapamil type. Approximately 5— 10% of the patients with outflow obstruction are refractory to such negative inotropic therapy (2). Positive inotropic drugs such as digitalis or sympathomimetics are strictly contraindicated. In the presence of atrial fibrillation, anticoagulation therapy should be started. Since endocarditis is more common in patients with HCM because of turbulence in the left ventricle, prophylactic antibiotics should be administered for periods of potential bacteraemia. 

First, however, consider that in turbulent Bunsen flames the axial component of the mean velocity along the centerline remains almost constant with height above the burner but away from the centerline, the axial mean velocity increases with height. The radial outflow component increases with distance from the centerline and reaches a peak outside the flame. Both axial and radial components of tuibulent velocity fluctuations show a complex variation with position and include peaks and troughs in the flame zone. Thus, there are indications of both generation and removal of turbulence within the flame. With increasing height above the burner. 

Although lakes are distinguished from rivers in part by the relative absence of a pronounced downstream flow of water, the waters of a lake are by no means stationary. Water currents, typically driven by wind instead of gravity, are a major feature of these water bodies. Water currents not only provide advective transport of chemicals in lakes but also cause transport by eddy diffusion because the water currents are almost always turbulent. In a lake, the average amount of time that water remains in the lake is called the hydraulic residence time, which can be estimated by the ratio of the lake volume to the rate at which water is lost through all processes (e.g., outflow, seepage, and evaporation). 

Assuming that the salt transport in the Baltic Sea occurs as a Conveyor Belt consisting of the inflow of salt water over the sills into the deepwater pool of the Baltic Sea, which is mainly carried by the turbulent influx in the Belt Sea, the vertical salt flux through the halocline into the brackish surface water of the Baltic Sea, and the outflow through the Belt Sea by advecting brackish surface water with the outflowing freshwater surplus q. Then we have balance between stochastic salt inflow and advective salt outflow Sg. 

Figliola has made steady flow velocity and shear stress measurements downstream from a 25 mm spherical disc aortic valve (47,89). At a flow rate of 25 1/min he measured a maximum wall shear stress of 722 dynes/cm and an occluder wall shear stress (resolved on the upper side of occluder) of 440 dynes/cm. He also monitored a maximum turbulent shear stress of 545 dynes/ cm2, a 25 mm downstream from the valve. His velocity measurements also showed a large region of stagnation across the outflow face of the disc. Tillman has measured the "wall" (i.e. surface) shear stresses along the orifice ring in the major and minor outflow regions of an aortic valve under pulsatile flow... 

In order to obtain a correlation, the outflow of the effervescent spray was simulated by a numerical model based on the Navier-Stokes equations and the particle tracking method. The external gas flow was considered turbulent. In droplet phase modeling, Lagrangian approach was followed. Droplet primary and secondary breakup were considered in their model. Secondary breakup consisted of cascade atomization, droplet collision, and coalescence. The droplet mean diameter under different operating conditions and liquid properties were calculated for the spray SMD using the curve fitting technique [43] ... 

Approximately 1 in 856 people will undergo kidney dialysis, resulting in over 354,000 patients in the US alone [59], During the process, blood is transferred and processed at a rate of 350 mL min via arteriovenous fistulas, which act as a permanent access point to the vasculature [60], Complications due to the hemodynamic stress (wall shear stress) induced by the dialysis needle have been observed. The presence of the outflow needle has been shown to increase turbulence intensities dramatically [61], which in turn increases wall shear stresses, induces intimal hyperplasia, and causes stenosis [60],... 

The study of the chemical and physical processes occurring in T Tauri outflows is of great importance as these stars have been proposed as the energy source of Herbig-Haro objects (Schwartz 1978 Canto 1978) and turbulence in molecular clouds (Norman and Silk 1980, Franco 1983). In this work, the physical model of the outflow is taken from Hartmann, Edwards and Avrett (1982) in which the primary stellar wind (i.e. wind that has not interacted with its environment) is ionized and heated by Alfven waves in the star s convection zone to reach a terminal velocity (of about 230 kms ) and a maximum temperature (of 20,000 K, cf. Hartmann et al. model no. 2) at z = 3 to 5, where z is the radial ordinate in units of stellar radii (r t 2 x 10 cm). Thereafter the wind expands and cools radlatively and adiabatically. Other parameters for the model are the initial wind density at z = 1 (oq lO - cm ), the density at z = 5 (n < 5 X 10 to 10 cm ) and the stellar photospheric temperature 4000 E). The cooling rate of the wind is obviously dependent on the physical conditions within the ejecta and in any case is by no means certain. Hartmann et al. suggest a... 

To quantify the effect of convective cooling of the LAD screen during dynamic outflow, the heat transfer rate across the screen is estimated for the LH2 LAD outflow test runs. Due to the high Re number (based on exit) for the tests, the Nusselt Nu) number based on hydraulic diameter derived by Petukhov and Popov (1963) is used, which assumes fully turbulent developed flow ... 

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