A numerical study of steady and unsteady viscoelastic flow past bounded cylinders

We consider two-dimensional, inertia-free, flow of a constant-viscosity viscoelastic fluid obeying the FENE-CR equation past a cylinder placed symmetrically in a channel, with a blockage ratio of 0.5. Through numerical simulations we show that the flow becomes unsteady when the Deborah number (using the usual definition) is greater than De≈1.3, for an extensibility parameter of the model of L2 = 144. The transition from steady to unsteady flow is characterised by a small pulsating recirculation zone of size approximately equal to 0.15 cylinder radius attached to the downstream face of the cylinder. There is also a rise in drag coefficient, which shows a sinusoidal variation with time. The results suggest a possible triggering mechanism leading to the steady three-dimensional Gortler-type vortical structures, which have been observed in experiments of the flow of a viscoelastic fluid around cylinders. The results reveal that the reason for failure of the search for steady numerical solutions at relatively high Deborah numbers is that the two-dimensional flow separates and eventually becomes unsteady. For a lower extensibility parameter, L2 = 100, a similar recirculation is formed given rise to a small standing eddy behind the cylinder which becomes unsteady and pulsates in time for Deborah numbers larger than De≈4.0–4.5

Germinação e comportamento das espécies Bagassa guianensis, Copaifera multijuga, Hymenaea courbaril, Dipteryx odorata e Tabebuia serratifolia, em Floresta plantada na Amazônia Oriental brasileira.

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Steady and unsteady laminar flows of newtonian and generalized newtonian fluids in a planar T-junction

An investigation of laminar steady and unsteady flows in a two-dimensional T-junction was carried out for Newtonian and a non-Newtonian fluid analogue to blood. The flow conditions considered are of relevance to hemodynamical applications and the localization of coronary diseases, and the main objective was to quantify the accuracy of the predictions and to provide benchmark data that are missing for this prototypical geometry. Under steady flow, calculations were performed for a wide range of Reynolds numbers and extraction flow rate ratios, and accurate data for the recirculation sizes were obtained and are tabulated. The two recirculation zones increased with Reynolds number, but the behaviour was non-monotonic with the flow rate ratio. For the pulsating flows a periodic instability was found, which manifests itself by the breakdown of the main vortex into two pieces and the subsequent advection of one of them, while the secondary vortex in the main duct was absent for a sixth of the oscillating period. Shear stress maxima were found on the walls opposite the recirculations, where the main fluid streams impinge onto the walls. For the blood analogue fluid, the recirculations were found to be 10% longer but also short lived than the corresponding Newtonian eddies, and the wall shear stresses are also significantly different especially in the branch duct

Dose Administration Aid system in the elderly: testing student active participation in the implementation of a new service for community pharmacy

Poster presented at the 9th PCNE (Pharmaceutical Care Network Europe) Working Conference

PARIWISATA BERBASIS EKONOMI KREATIF DI KOTA TOMOHON

ABSTRAK Ekonomi ikreatif iadalah isuatu ikreativitas ikarena imenghasilkan isuatu iproduk iyang ikreatif idan iinovatif iberbasis ikearifan ilokal. iEkonomi ikreatif iyang iditeliti idalam ipenelitian iini iadalah iekonomi ikreatif idi isektor iarsitektur, ikriya, idesain iproduk, idan ikuliner. iKota iTomohon iadalah isalah isatu ikota iyang iberada idi iProvinsi iSulawesi iUtara iyang imemiliki iberagam ipotensi ipariwisata iekonomi ikreatif, ikeunikan idan ikearifan ibudaya ilokal isehingga idipilih isebagai itempat ipelaksanaan iprogram iinovatif idan ikreatif iyang idi iselenggarakan ioleh iBadan iEkonomi iKreatif isebagai ikomitmen iPemerintah iterhadap iEkonomi iKreatif. iPenelitian iini ibertujuan iuntuk imengidentifikasi ijenis idan imenganalisis ipotensi ipariwisata iberbasis iekonomi ikreatif idi iKota iTomohon. iMetode ipenelitian iyang idipakai iadalah imetode ipenelitan iDeskriptif ikualitatif. iMetode ipengumpulan idatanya iadalah iwawancara idengan ibeberapa istakeholder, iobservasi, idan idokumentasi. iTeknik ianalisis idata iyang idigunakan iadalah ireduksi idata, ipenyajian idata, iverifikasi iatau ipenyimpulan idata, ianalisis iSWOT. iHasil idari ipenelitian iini imenunjukan ibahwa isetiap ipengembangan isektor iekonomi ikreatif idi iKota iTomohon imemerlukan i iadanya ikerja isama iantara ipengelola idengan imasyarakat isekitar idan ipihak-pihak iterkait idalam iproses ipengembangan iwisata ikreatif iKota iTomohon, iserta imengoptimalkan ipotensi iwisata ikreatif iyang idimiliki idengan imemanfaatkan idukungan iyang idiberi ioleh ipemerintah.ABSTRACTCreative economy is creativity because it produces a creative and innovative product based on local wisdom. The creative economy studied in this study is the creative economy in the architectural, craft, product design, and culinary sectors. Tomohon City is one of the cities in North Sulawesi Province which has a variety of creative economic tourism potential, uniqueness and local cultural wisdom so that it was chosen as a place for implementing innovative and creative programs organized by the Creative Economy Agency as a Government commitment to the Creative Economy. This study aims to identify and analyze creative economy-based tourism in Tomohon City. The research method used is a qualitative research method using a descriptive approach. Data collection methods are interviews with several stakeholders, observation, and documentation. Data analysis techniques used are data reduction, data presentation, verification or data inference, SWOT analysis. In general, the strategy from the results of this study shows that every development of the creative economy sector in Tomohon City requires cooperation between managers and the surrounding community and related parties in the process of developing Tomohon City creative tourism, as well as optimizing the potential of creative tourism owned by utilizing support provided by the government.Keywords: Creative Economy, Tourism, SWOT

Rotating Hele-Shaw cells with ferrofluids

We investigate the flow of two immiscible, viscous fluids in a rotating Hele-Shaw cell, when one of the fluids is a ferrofluid and an external magnetic field is applied. The interplay between centrifugal and magnetic forces in determining the instability of the fluid-fluid interface is analyzed. The linear stability analysis of the problem shows that a non-uniform, azimuthal magnetic field, applied tangential to the cell, tends to stabilize the interface. We verify that maximum growth rate selection of initial patterns is influenced by the applied field, which tends to decrease the number of interface ripples. We contrast these results with the situation in which a uniform magnetic field is applied normally to the plane defined by the rotating Hele-Shaw cell.Comment: 12 pages, 3 ps figures, RevTe

Observation of slow light in the noise spectrum of a vertical external cavity surface emitting laser

The role of coherent population oscillations is evidenced in the noise spectrum of an ultra-low noise lasers. This effect is isolated in the intensity noise spectrum of an optimized single-frequency vertical external cavity surface emitting laser. The coherent population oscillations induced by the lasing mode manifest themselves through their associated dispersion that leads to slow light effects probed by the spontaneous emission present in the non-lasing side modes.Comment: accepted for publication in Phys. Rev. Let

Unparticle physics and neutrino phenomenology

We have constrained unparticle interactions with neutrinos and electrons using available data on neutrino-electron elastic scattering and the four CERN LEP experiments data on mono photon production. We have found that, for neutrino-electron elastic scattering, the MUNU experiment gives better constraints than previous reported limits in the region d>1.5. The results are compared with the current astrophysical limits, pointing out the cases where these limits may or may not apply. We also discuss the sensitivity of future experiments to unparticle physics. In particular, we show that the measurement of coherent reactor neutrino scattering off nuclei could provide a good sensitivity to the couplings of unparticle interaction with neutrinos and quarks. We also discuss the case of future neutrino-electron experiments as well as the International Linear Collider.Comment: 20 pages, 5 figures. Minor changes, final versio

Numerical and analytical modeling of unsteady viscoelastic flows: the start-up and pulsating test case problems

In this paper two test cases adequate for the assessment of viscoelastic flow codes under unsteady flow conditions are investigated. For one of them an analytical solution is also derived. First, the start-up of planar Poiseuille flow between two parallel plates was tackled. For upper-convected Maxwell and Oldroyd-B models there exist analytical solutions making it possible to evaluate exactly the discretization errors of the transient numerical method. Good agreement was found between the present numerical results and those analytical solutions, especially for “shock” propagation. For the UCM fluid, small numerical oscillations were observed at points where the time derivative of velocity was discontinuous, but for the Oldroyd-B fluid a smooth development of the transient evolution was obtained. Results with the PTT model without solvent viscosity and the FENE fluids were also obtained and, as expected, the behaviour was similar to that found for the UCM and Oldroyd-B fluids, respectively. Then, a pulsating flowproblemwas studied. In this test case the flow is generated by a periodic ressure gradient superimposed on a constant Poiseuille flow. The analytical solution for pulsatile Oldroyd-B flow in a channel was derived as part of the work and, again, difficulties in obtaining accurate numerical solutions with the UCM model were encountered, being necessary to employ extremely refined meshes. For the Oldroyd-B fluid no difficulties were found and the accuracy tended to improve with larger solvent viscosity parameter