Identification and Characterization of Pastureland and Other Grazing Resources of Jammu & Kashmir Using GIS and Satellite Remote Sensing Technique

Livestock acquires special importance in mountain farming system from both ecological and socioeconomic point of view. They are an integral part of the farming system and a “bridge’’ connecting two types of land viz., forest and cultivated. In hilly regions, the arable agriculture is not very remunerative; therefore farmers of all categories rear sheep, goats, cattle etc. under sedentary, semi-migratory and migratory systems to supplement family income (Dev et al., 2014). The common property resources (CPR) and degraded pasturelands are the major feed sources. Remotely sensed satellite imagery and Geographic Information System (GIS) are being widely used for the assessment of pasturelands and estimation of forage availability as well as monitoring of the range resources (Singh et al., 2011). Since, the grazing resources are limited and natural grasslands are becoming scarcer, there is a greater need to effectively manage grasslands for optimum forage production and eco-development (Roy and Singh, 2013). Precise information on extent, condition and forage availability is essential for developmental planning. In the present study information on current status of pasturelands in Jammu and Kashmir based on remotely sensed satellite data and GIS/GPS is carried out

Response of active control on the flow field of the duct pressure at supersonic Mach numbers

In this study, experiments were conducted to control the base pressure and wall pressure in the wake at considerably high Mach numbers for a duct diameter of 25 mm. Tests were done at Mach 1.87 and 2.2. The Nozzle Pressure Ratios considered are 3 to 11 at different expansion levels. These experiments were conducted to evaluate the flow mechanism’s efficacy while the nozzle is under the impact of favorable and adverse pressure. The control mechanism was positioned at 6.5 mm from the central axis of the main jet. Results reveal that the minimum pipe length required for the flow to remain attached with the duct is L = 2D. When the duct is L = 2D or 3D, the flow pattern is erratic due to the incident’s excessive interaction of the reflected shock waves, and the impact of the ambient pressure. Because of the high duct diameter, the control is not efficient even though nozzles are under-expanded. For a larger area ratio, the reattachment length will be large, hence control becomes marginally effective. For over-expanded jets, the control results to reduce the pressure inside the duct. When nozzles encounter high-intensity adverse pressure results in high wall pressure compared to the lower nozzle pressure ratio due to the decline in the strength of the wave. When nozzles are under-expanded, the control effectiveness is optimum. The control mechanism is employed is able to suppress oscillations for large ducts compared to the short duct, where the flow is oscillatory. The control mechanism also results in the reduction of jet noise for some selected cases

Benefit of Mach number and expansion level on the flow development in a cylindrical tube diameter of 18 mm

In this paper, experiments are performed at high Mach numbers to examine the flow control effect located in the separated region at 6.5 mm from the central jet. A circular orifice is placed in the wake region to manipulate the base flow to boost the wake area’s pressure and ultimately reduce the base drag. The study also investigates the impact of micro-jets on the stream of the tube. Accordingly, tests are conducted using C-D nozzles fabricated at Mach 1.87, 2.2, and 2.58. Flow generated from these nozzles is exhausted in a duct whose diameter is 18 mm. The results show that for duct length 6D and above, the flow field inside the duct becomes oscillatory, whereas such fluctuations are not noticed when duct size is less than 4D. Dynamic control shows mixed trends when jets are operating at design NPR or under the impact of favorable pressure. And within reattachment length, active flow control is not able to impact the flow pattern. When nozzles are running underneath, over-expansion and flow control are initiated; it decreases the duct’s pressure. The smallest duct size essential for the stream to continue connected appears to be 1D for Mach 1.87 and Mach 2.2 and 2.58; this requirement is 2D