Second order structure functions for higher powers of turbulent velocity

We experimentally study the temporal second-order structure functions for integer powers of turbulent fluid velocity fluctuations [Formula: see text], in three dimensional (3D) and two dimensional (2D) turbulence. Here [Formula: see text] is a composite time-series constructed by averaging the concurrent time-series ([Formula: see text]) sampled at N spatially distributed Eulerian points. The N = 1 case has been extensively studied for velocity fluctuations (m = 1) and to a lesser extent for m > 1. The averaging method in case of N > 1 diverges from the Kolmogorov framework and has not been studied because fluctuations in [Formula: see text] are expected to smooth with increasing N leaving behind uninteresting large-scale mean flow information, but we find this is not so. We report the evolution of scaling exponents [Formula: see text] for [Formula: see text] in going from a single (N = 1) to a spatial average over several Eulerian points ([Formula: see text]). Our 3D experiments in a tank with rotating jets at the floor show [Formula: see text] for all m-values in agreement with prior results and evolves to an asymptotic value of [Formula: see text]. The evolution of [Formula: see text] follows the functional form [Formula: see text], where [Formula: see text] points is the only fit parameter representing the convergence rate constant. Results for the 2D experiments conducted in a gravity assisted soap film in the enstrophy cascade regime are in sharp contrast with their 3D counterparts. Firstly [Formula: see text] varies polynomially with m and asymptotes to a constant value at m = 5. Secondly, the evolution of [Formula: see text] is logarithmic [Formula: see text], where A and B are fit parameters and eventually deviates at large N and asymptotes to [Formula: see text] for all m. The starkly different convergence forms (exponential in 3D versus logarithmic in 2D) may be interpreted as a signature of inter-scale couplings in the respective turbulent flows by decomposing the two-point correlator for [Formula: see text] into a self-correlation and cross-correlation term. In addition to aiding in the theoretical development, the results may also have implications for determination of resolution in 2D turbulence experiments and simulations, wind energy and atmospheric boundary layer turbulence

Pemantauan Perubahan Garis Pantai Menggunakan Aplikasi Digital Shoreline Anaysis System (Dsas) Studi Kasus : Pesisir Kabupaten Demak

Shoreline changes in Demak which is caused by abrasion and accretion processes and triggered due to intensive human activities in coastal areas. It is also caused by the tidal flood that often occur in this area and the influence of physical characteristic of the ocean. Abration and accrestion occurs in almost all coastal areas and it happen quite drastic.This research use remote sensing method as a quick study to detect the shoreline changes in Demak with Landsat 7 images in 2011-2012 and Landsat 8 images in 2013-2015 as the primary data. Shorelines information obtained by using rationing method to delineated the water and the land. The 2011 shoreline used as a starting point to calculate the changes between 2012-2015 shorelines. This research use Digital Shoreline Analysis System (DSAS) to calculate the rate-of-changes between the shorelines.The results showing the most significant changes occur in Wedung, Demak with maximum accretions 233.9941 meter and maximum abrations 141.037 meter. The biggest changes at predicton of shoreline changes between 2016-2020 is transect A with accretion +280.92 meter and the lowest is transek H with abration -0.004 meter. Abration and accretion happen because of the lack to maintain the mangrove ecosystem in coastal areas of Demak whose function turned into area of ponds or settlement

Evaluasi Berbagai Dosis Nitrogen Untuk Teknik Produksi Tanaman Cabai Yang Menggunakan Mulsa

Kebanyakan petani tetap menggunakan dosis pupuk nitrogen sesuai rekomendasi dalam produksi cabai dengan menggunakan mulsa plastik hitam perak. Hasil penelitian sebelumnya mengindikasikan bahwa penggunaan mulsa mampu mengurangi pencucian nitrogen. Dengan demikian, perlu upaya untuk mencari seberapa banyak penurunan nitrogen yang dapat diberikan kepada cabai yang diproduksi dengan menggunakan mulsa. Penelitian dilaksanakan di Kota Bengkulu dari Maret sampai September 2004 menggunakan rancangan acak kelompok lengkap dengan dua faktor dan tiga ulangan. Faktor pertama adalah jenis mulsa yang digunakan ; mulsa plastik hitam perak, mulsa jerami padi dan tanpa mulsa. Faktor kedua adalah dosis nitrogen ; 115 kg/ha (dosis rekomendasi), 103,5 kg/ha, 92 kg/ha, dan 80,5 kg/ha. Hasil penelitian menunjukkan bahwa tidak terdapat interaksi antara jenis mulsa dengan dosis nitrogen dalam meningkatkan atau menurunkan semua variabel yang diamati. Cabai yang ditanam dengan menggunakan mulsa jerami memiliki jumlah cabang dikotom yang lebih tinggi dibanding tanaman yang ditanam tanpa mulsa, tetapi tidak berbeda dengan cabai yang ditanam dengan mulsa plastik hitam perak. Meskipun tidak ada interaksi antara jenis mulsa yang digunakan dengan dosis nitrogen dalam meningkatkan atau menurunkan variabel yang diamati, penggunaan 80,5 kg/ha nitrogen (30 persen lebih rendah dari dosis rekomendasi) meningkatkan jumlah dan bobot buah tanaman cabai

Pembuatan Aplikasi Sistem Informasi Geografis Persebaran Lembaga Kursus Bahasa Inggris Berbasis Android (Studi Kasus Desa Tulung Rejo Dan Desa Pelem Kecamatan Pare Kabupaten Kediri )

Tulung Rejo village and Pelem village were located in Pare District, Kediri Regency, East Java. On these villages which were generally known as "Kampung Inggris", spreaded 104 english courses. By having wide-large area and large number of the courses, it still have less informations such as the names, locations, and facilities of those courses. In order to accomplish this problem, it was needed geographic information system to manage and provide spatial and non spatial data.This research used coordinate data which was gotten by GPS handheld. First step was by designing an application, which consisted of use case scenario, activity diagram, class diagram, and user interface. The second was by coding the application using HTML 5 by framework ionic. The last was by running the application using emulator of pc for ensuring the application was match with the first plan. After it perfectly fixed, it can be appropriately compatible on AndroidThe output of this research was a mobile GIS application which had an informations about the courses at Tulung Rejo Village and Pelem Village. It offered the names, locations, facilities, and some other supporting informations. It was expected this application can provide useful informations and hopefully this research can be developed in the future

Where surface physics and fluid dynamics meet: rupture of an amphiphile layer by fluid flow

We investigate the fluctuating pattern created by a jet of fluid impingent upon an amphiphile-covered surface. This microscopically thin layer is initially covered with 50 $\mu$m floating particles so that the layer can be visualized. A vertical jet of water located below the surface and directed upward drives a hole in this layer. The hole is particle-free and is surrounded by the particle-laden amphiphile region. The jet ruptures the amphiphile layer creating a particle-free region that is surrounded by the particle-covered surface. The aim of the experiment is to understand the (fluctuating) shape of the ramified interface between the particle-laden and particle-free regions.Comment: published in Journal of Chemical Physic

Analisis Pola Arus Laut Permukaan Perairan Indonesia Dengan Menggunakan Satelit Altimetri Jason-2 Tahun 2010-2014

Ocean Current is a mass movement of flowing water caused by wind, differences in density, or long wave movement. At the present time many ocean currents used for various purposes that support human life. However, current data acquisition using conventional tools is very difficult for the vast territory and require a huge cost, therefore we use data from altimetry satellites. With the development of altimetry satellite system, one of the Jason-2 altimetry satellites which offer data on wind direction and the speed of wind that will go through the calculation method to get the surface ocean currents data of Indonesian waters.This study took place in Indonesian waters which is located within 6 ° 08 'N - 11 ° 15' S and 94 ° 45 'E - 141 ° 05' E. The data used in this research is GDR (Geophysical Data Record) data of Jason-2 altimetry satellites in 2010-2014. GDR data contains 36 pass (the orbital paths) in a single cycle, which one cycle can be reached within ten days. The method used is the calculation of the direction and speed of ocean currents surface of each cycle with Stewart equation.The results of this study indicate that when West monsoon occurs from December to February, the wind is blowing from the West to the East, so the current is also moving from the Asian continent towards the Australian Continent. In the event of East monsoon which is from June to August, the wind is blowing from the East to the West, so the current is also moving from the Australian continent towards the Asian continent. Meanwhile, during a transitional season either the transition from monsoon West to monsoon East which is from March to May and during the transition from monsoon East to monsoon West which is from September to November, the current's movement is irregular and tend to fall into two directions, ie from the Asian continent towards Australian continent and from the Australian continent to the Asian continent, but the average speed of the current is weak in almost all Indonesian waters. The current pattern of sea surface modeling results indicate some current directions are not the same as Wyrtki current model, but some current directions are also the same as Wyrtki current model in several water location samples such as Arafuru Sea, the water around the Java island, the water west of the Sumatra island, the water north of the Papua island, and the Strait of Karimata

Analisis Harmonik Dengan Menggunakan Teknik Kuadrat Terkecil Untuk Penentuan Komponen-komponen Pasut Di Wilayah Laut Selatan Pulau Jawa Dari Satelit Altimetri Topex/poseidon Dan Jason-1

South Java's sea is one of Indonesia's territorial waters which is part of Indian Ocean. It has a lot of potentials in terms of ecology, physics, and vulnerability to natural disasters. Tide is one phenomenon that can be used as a reference in policy decisions regarding the management of natural resources and as supplementary data to describe the condition of the sea in the future.The aim of this research was to determine the components and south Java's sea tide types. The data used is Sea Level Anomaly (SLA) data from satellites Topex/ Poseidon in 1992-2002 and data satellite Jason-1 in 2002-2011. Inverse Distance Weight (IDW) interpolation method is used to determine the SLA at the normal point followed by harmonic analysis process using least squares with weighted technique to determine the components of the tides. Calculation of harmonic analysis process was using Microsoft Excel 2010 combined with Matlab 7.6.0 application for the interpolation of data.The result of this research showing there are 21 components that influence the formation of the tide in waters Cilacap, Sadeng, and Prigi which is consists of 9 long period component, 8 diurnal component, and 9 semidiurnal components. While the type of tidal formed in the waters south of the island of Java, which is a mixed tide prevailing semidiurnal