Erosion of a sharp density interface by homogeneous isotropic turbulence

Desalination, commonly used for potable water production, generates brines that are ultimately released back into the environment. Desalination brines discharged into coastal regions with weak currents and mild bathymetry, such as the Gulf of Mexico, do not necessarily mix with surrounding natural waters and remain stably stratified (Hodges et al., 2011). Because dense immobile saline layers from these discharges can cause hypoxia and threaten local ecosystems, we are conducting an experimental study to investigate the effect of turbulence on a sharp density interface to identify mechanisms of turbulence that promote and/or inhibit interfacial erosion. There remains a gap in the literature regarding the interaction of mean shear free homogeneous isotropic turbulence with a sharp density interface, a critical component in understanding dynamics across a stably stratified system. To address this fundamental question, we use randomly actuated synthetic jet arrays (RASJA - Variano & Cowen (2008)) to generate homogeneous isotropic turbulence, absent mean shear, above a dense fluid layer. The Richardson number is varied to ascertain the thresholds at which the density interface erodes and mixing between the stratified layers occurs. As in Johnson & Cowen (2018), who characterized the mean shear free turbulent boundary layer at solid and sediment beds, particle image velocimetry is used to complete a statistical analysis of the turbulent flow field at and above density interface. Simultaneous laser induced fluorescence measurements are obtained to capture erosion, sharpening, and mixing. Statistical metrics of the turbulence are coupled with the evolution of concentration profiles and mixing, which is determined by measuring temporally resolved isopycnal displacements. In the current work, we provide the first experimental data to test quantifying entrainment across stratified fluids as described and applied in direct numerical simulation studies by Zhou et al. (2017). By examining the interplay between mean shear free homogeneous isotropic turbulence and a sharp density gradient, we aim to deduce under what environmental conditions it is sustainable to discharge brine into relatively quiescent flows, considering key factors such as ambient turbulence and relative salinity variance between the brine and surrounding waters.Environmental and Water Resources Engineerin

Traditional fishing methods and gears utilized in edible bivalve fishery at Bhatye estuary, Ratnagiri, (M.S.)

1672-1678Locally available devices were utilized by fishers for bivalve fishery at Bhatye estuary, Ratnagiri coast. Fishers of Bhatye estuary were performing three kinds of bivalve fishing activities like clam fishing, oyster fishing and mussel fishing. In these fishing activities, the fishers were implemented the old age fishing techniques and locally developed fishing gears for harvesting the clams, oysters and mussel resource from fishing ground. The traditional based fishing practices will maintain the natural stock and it help in sustainable utilization of bivalve resource without damaging the ecosystem

Commercial harvesting and economy of edible clam species in Bhatye estuary, Ratnagiri (MS), India

665-669Present study consists the annual harvesting and economics of commercially important edible clam species from Bhatye estuary, Ratnagiri (M.S.). Data collected by field and household survey and results were interpreted in two periods viz. July-Dec, 2008 and Jan-June, 2009. In Bhatye estuary, K. opima, M. meretrix, M. casta, P. laterisulca and P. textile are 05 edible clam species dominantly occurred while these species are commercially harvested on large scale by fishers of Bhatye village. Out of 350 families in village; 15.14% (53) families with 63 individuals engaged in clam fishing. Among this male individual’s contribution was maximum than females. Annually 60.354 tones of catch were harvested by fishers. Maximum catch was harvested during Jan-June rather than Aug-Dec. In species wise catch, the Meretrix sps. were highly exploited than Paphia and Katelysia sp. respectively. Higher income was received from the above during Jan-June period. Meretrix clam received maximum income respect to other species

Seasonal variations in meat yield and body indices of three estuarine clam species (Bivalvia: Veneridae)

1586-1593<span style="font-size:11.0pt;mso-bidi-font-size: 10.0pt;font-family:" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";="" mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="" lang="EN-GB">In the present study, meat yield (MY) and body indices like Body Condition Index (BCI), Hepatopancreas Index (HI), Gonadal Index (GI) and shell Component Index (SCI) were studied monthly in three commercially important venerid clams species (M. meretrix, K. opima and P. laterisulca) from Bhatye estuary. Results reveal that the highest meat yield in clams like M. meretrix, K. opima and P. laterisulca was recorded during July, August and September, 2010. Maximum BCI was observed in the months of December, June and September from M. meretrix, K. opima and P. laterisulca respectively. Maximum HI and GI were recorded during April and August in M. meretrix, during July and August in K. opima and during January and June in P. laterisulca. Highest value of SCI was acquired in M. meretrix and P. laterisulca during April, while in K. opima during February. In the present investigation, peak values of meat yield and body condition index were determined as an indicative of nutritive status of the clam species. Hence, greatest availability of nutrients in clams during annual cycle is the most feasibly or ideal period for harvesting commercially important clam species. </span

Oxygen consumption rate of the estuarine Psammobiid clam <i>Soletellina diphos </i>(linnaeus) under various Environmental conditions

468-472Oxygen consumption rate (OCR) of the estuarine clam, Soletellina diphos (Linnaeus) was studied in the laboratory. The OCR was measured against a range of body size and weight, and under conditions of starvation, aerial exposure, temperature and low salinity. The pattern of diurnal rhythm was also investigated. The OCR was found to be inversely related to body size and body weight. It decreased considerably with starvation but, with exposure to atmospheric air, it increased up to 3rd hour and reached to the normal level by the 5th hour. The OCR increased with rise in temperature from 20 oC to 35 oC. It altered with decrease in salinity as compared to normal salinity (38 ‰), it was highest at 70 % and lowest at 40 % of normal seawater. A distinct diurnal rhythm in OCR was observed in these clams. The OCR was greater around afternoon and at a lowest level around midnight