scholarly journals GRAPHICAL ANALYSIS OF FREE-SURFACE WAVE FIELDS FROM MOVING SHIPS AND A PAIR OF CONSECUTIVE POSTS

2019 ◽  
Vol 2019 (4) ◽  
pp. 7-22
Author(s):  
Павел Бимбереков ◽  
Pavel Bimberekov
Keyword(s):  
Water Transport ◽  
Water Surface ◽  
Free Water ◽  
Wave Pattern ◽  
Graphical Analysis ◽  
Wave System ◽  
Kelvin Wave ◽  
Experimental Tank ◽  
Wave Patterns ◽  
Pattern Forming

The paper presents a comparison of the photographic material of the wave patterns resulted from the movement of a ship in situ and a model ship, as well as from two consecutive posts, their regularities being found through graphical processing. The possibility to find the fore imaginary source of Kelvin wave pattern forming the ship's wave system is given at a distance of one wavelength before the top of the bow retaining wave. The equality of the length of trans-verse waves and divergent waves along the outer boundaries of the latter zone is fixed. It has been assumed that the intermediate waves generated between the main waves in the model ship and the posts are regular, imposition of wave patterns in a pair of consistently moving racks depending on the hit of the rear rack in the wave field of the first rack has been stated. Regularly occurring flows around moving posts are discussed. The bow and stern system of Kelvin waves in a ship wave sys-tem has been illustrated (the angle of the midpoint of diverging wave crests with the ship’s diamet-rical plane and the angle of diverging wave crests with the ship’s diametrical plane). The photo-graphs presented were taken in the experimental tank of Siberian State University of Water Transport (Novosibirsk State Academy of Water Transport) in 2006. A thin film naturally generat-ed on the water surface of the experimental tank and given a structure directed along the tank due to previous runs helped to visualize the distortion of the free water surface in better quality and to obtain clearly outlined contours in lighting.

scholarly journals Graphical analysis of free-surface wave fields from moving two consecutive posts connected by thin plate

2020 ◽  
Vol 2020 (1) ◽  
pp. 45-53
Author(s):  
Pavel Bimberekov
Keyword(s):  
Wave Field ◽  
Water Transport ◽  
Cross Section ◽  
Thin Plate ◽  
Wave Pattern ◽  
Graphical Analysis ◽  
Wave System ◽  
Kelvin Wave ◽  
Horizontal Section ◽  
Shaped Cross Section

The article presents photographic materials of wave pictures from two consecutive posts of teardrop cross-section and the same posts with a thin plate installed between them, which introduces into consideration not only separate sequentially moving sources, but also reunites them into a single object, interacting along its entire length with the system of waves from the first source. The regularities of the wave field of consecutive posts with a plate in-stalled between them by means of graphic processing are considered. The possibility of finding the front imaginary source of the Kelvin wave pattern forming the ship's wave system at the position of both one and two wave-lengths in front of the top of the bow retaining wave is estimated. A method is proposed for determining the position of the fictitious location of the aft Kelvin wave system of the ship's wave system based on the results of the analysis of the wave field at the characteristic speeds of movement, leading to the most successfully fixed inter-location of the wave pattern from the bow and aft extremities. There are shown the pictures of moving forward a pair of posts with a blunt end of a horizontal section at the same speed and photo fixation from a close angle, pictures of moving forward the posts with a plate between them with a blunt end of a teardrop-shaped cross section at a low speed, moving forward posts with a plate at the side with a sharp end of a teardrop-shaped cross section, etc. All presented photographs were taken in the experimental pool of the Siberian state University of water transport (Novosibirsk state Academy of water transport) in 2006.

scholarly journals Analysis of wave fields of free water surface from moving plate, pair of consecutive posts and discussion of likely components of their wave resistance

2020 ◽  
Vol 2020 (2) ◽  
pp. 30-38
Author(s):  
Pavel Bimberekov
Keyword(s):  
Water Transport ◽  
Free Water ◽  
Wave Resistance ◽  
State University ◽  
Total Resistance ◽  
Kelvin Wave ◽  
Moving Plate ◽  
Transverse Waves ◽  
Plate Length ◽  
Wave Patterns

The paper presents and compares photographs of wave patterns from a moving plate with pointed and full ends, from which, with the exception of a cylindrical insert, there develops a post with a teardrop-shaped cross-section, as in a pair of tandem posts. The plate length equals to the overall size of the specified pair of consecutive posts. The conclusion is made about the possibility of selecting a unified wave resistance component from the total resistance, which can be determined experimentally based on the results of the study of a combination of individual posts and/or other objects of the specified shape. Possible variants of wave resistance components are being discussed. Besides, a variant of modeling the ship's wave resistance by representing two pairs of such wave systems rather than two Kelvin wave systems on a free surface is proposed. Additional fore and aft Kelvin wave systems are proposed to be shifted against the course of motion by half the wavelength. These additional wave systems are intended to describe internal intermediate waves located between the main transverse waves. There have been presented the expressions for wave resistance that contain some proportionality coefficients, possible components of wave resistance from smoothing diverging waves within the smoothing zone of wave structures, starting from the bow extremity and other unaccounted components of wave resistance. The photos proposed were taken in the experimental pool of Siberian State University of Water Transport (Novosibirsk State Academy of Water Transport) in 2006

scholarly journals WATER WAVES DUE TO A LOCAL DISTURBANCE

2011 ◽  
Vol 1 (6) ◽  
pp. 8
Author(s):  
J. E. Prins
Keyword(s):  
Water Waves ◽  
Water Surface ◽  
Wave Pattern ◽  
Wave System ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Local Disturbance ◽  
Wave Characteristics ◽  
Two Dimensional Model ◽  
Made In

A model investigation of the characteristics of waves generated by a local disturbance was made in order to obtain comparison with the theories of UNOKI and NAKANO (1953) and KRANZER and KELLER (1955). The two-dimensional model for the case of initial local elevation or depression of uniform height of the water surface showed that certain wave characteristics such as phase periods and "interference" pattern could be described reasonably well within certain limits of water depth and height and extent of the disturbed area. Beyond those limits the leading part separated from the generated wave pattern as a solitary wave or a more complicated wave system. For a certain range of conditions the leading part was preceded by a bore during the first portion of the travel.

A Review of the Kelvin Ship Wave Pattern

1991 ◽  
Vol 35 (03) ◽  
pp. 191-197
Author(s):  
Yong Kwun Chung ◽  
Jin Soo Lim
Keyword(s):  
Point Source ◽  
Wave Pattern ◽  
Single System ◽  
Kelvin Wave ◽  
Ship Wave ◽  
Pressure Point ◽  
Wave Patterns ◽  
Wave Induced

This paper finds that the Kelvin ship wave induced by a moving pressure point consists of a single system of divergent waves but that there are infinitely many different Kelvin wave patterns for a submerged point source.

EFEKTIVITAS TANAMAN GENJER DALAM MENURUNKAN BOD DAN COD LIMBAH CAIR TAHU HASIL PROSES ANAEROB

2016 ◽  
Vol 4 (1) ◽  
Author(s):  
Muhammad Irvan Nurliansyah
Keyword(s):  
Water Surface ◽  
Free Water ◽  
Surface Flow ◽  
Free Water Surface

ABSTRAK Limbah cair tahu merupakan limbah cair yang berasal dari proses pembuatan tahu. Limbah cair tahu mengandung senyawa organik yang tinggi. Pembuangan limbah cair tahu secara langsung ke badan air tanpa dilakukan pengolahan dapat mempengaruhi dan mencemari lingkungan. Suatu cara untuk menanggulangi permasalahan tersebut adalah melakukan pengolahan limbah cair tahu. Salah satu alternatif pengolahan limbah cair tahu yang dapat digunakan adalah fitoremediasi menggunakan tanaman genjer. Penelitian ini bertujuan untuk mengetahui efisiensi pengolahan dan efektivitas waktu tinggal pengolahan limbah cair tahu menggunakan tanaman genjer dalam menurunkan BOD dan COD effluen hasil proses pengolahan anaerob limbah cair tahu. Metode yang digunakan dalam penelitian ini adalah fitoremediasi menggunakan tanaman genjer pada sistem lahan basah buatan Free Water Surface flow dengan waktu tinggal 3 hari, 5 hari dan 7 hari. Hasil penelitian menunjukkan bahwa efisiensi pengolahan secara fitoremediasi pada hari ke 3 untuk BOD dan COD berturut-turut sebesar 21,28% dan 16,13%. Pada hari ke 5 efisiensi pengolahan yang diperoleh untuk BOD dan COD berturut-turut sebesar 52,60% dan 45,93% sedangkan efisiensi pengolahan pada hari ke 7 untuk BOD dan COD berturut-turut sebesar 76,42% dan 70,74%. Waktu tinggal efektif yang diperoleh pada penelitian ini adalah  7 hari dengan nilai BOD dan COD telah berada dibawah baku mutu yaitu berturut-turut sebesar 72,72 mg/l dan 213,33 mg/l.   Kata kunci : limbah cair tahu, fitoremediasi, tanaman genjer, efisiensi pengolahan, waktu tinggal

Remote turbidity measurement with a laser reflectometer

1998 ◽  
Vol 37 (12) ◽  
pp. 255-261 ◽  
Author(s):  
Mark Johnson
Keyword(s):  
Water Surface ◽  
Free Water ◽  
Optical Scattering ◽  
Flowing Water ◽  
Water Stream ◽  
Water Turbidity ◽  
Water Colour ◽  
Contact Measurement ◽  
Optical Instruments ◽  
Better Than

A simple, laser-based reflectometer is described for the measurement of water turbidity via 180° optical scattering. Applications exist both in clean source waters (0-1000NTU) with a minimum detectable turbidity better than 1NTU, and in dense wastewater primary-clarifier sludges. The non-contact measurement is performed from a distance at least up to 10m, substantially avoiding the usual window fouling problems of optical instruments. By measuring directly in the process, through a free water surface or on the side of a flowing water stream, the difficulties of transporting sample to the instrument are also avoided. Extensions to be described allow measurement also of water colour.

A Free Water Surface Constructed Wetland in Treating Sugarcane Wastewater

2011 ◽  
Vol 33 (1) ◽  
pp. 71-86
Author(s):  
Doorce S. Batubara ◽  
Donald Dean Adrian
Keyword(s):  
Constructed Wetland ◽  
Water Surface ◽  
Free Water ◽  
Free Water Surface
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