1.2m Trisonic wind tunnel of CSIR-National Aerospace Laboratories, Bengaluru is the work horse for all the national Aerospace programs since 1967. All the major high-speed flight vehicles developed by DRDO, ISRO, HAL and ADA have graduated out of this facility. The highest speed of this tunnel is Mach 4.0 which is four times the speed of sound. The mission of this facility is to provide advanced technology solutions to national aerospace programs, like fighter aircraft, defence systems, launch vehicles and space systems. The contribution of this facility to LCA-Tejas fighter aircraft, PSLV, GSLV, RLV launch vehicles, missiles like Agni, Prithvi, AKASH, Brahmos, etc is remarkable.
This facility after having achieved a significant milestone of 56 years of successful operation and crossing 56000 blowdowns now celebrates successful launch of Chandrayaan mission. The main launch vehicle LVM3 that carried Chandrayan-3 module was extensively tested and characterised in this facility. The LVM3 testing started in the year 2001. The LVM3 (GSLV MK3) designed for geo synchronous orbital missions has a 5-metre diameter payload fairing to be able to accommodate large payload modules like space station segments.
More than 3000 wind tunnel tests were carried out to characterize the LVM3 vehicle which included force measurements, steady and unsteady pressure measurements, booster-load measurements, booster misalignment studies, aero-elastic and nozzle load studies apart from surface and off-surface flow visualisation studies. Based on these wind tunnel tests, the configuration underwent major design changes during year 2014-2015. Subsequently, the control law was modified and structure was cleared for the test flight.
The Acoustic Test Facility (ATF) with a 1100 cu.meter. reverberation chamber at CSIR-NAL simulates, the fluctuating sound pressure field experienced by the payload/launch vehicle during lift-off and atmospheric flight. Rocket blast creates large sound pressure: 100,000 times more powerful than normal speech. This can damage the payload and launch vehicle subsystems. The facility is capable of providing acoustic qualification of all of ISRO’s space bound hardware with spectra confirming to MIL-STD 810G standards. This facility has completed more than 3000 acoustic blowdowns and characterised more than 100 flight vehicles, and subsystems of ISRO. All stages of LVM3 with Chandrayaan 3 payload fairing were acoustically characterized in this facility and cleared for launch which was crucial for the mission. (All photographs are from open source)
CSIR-NAL family proudly celebrates success of Chandrayaan launch and congratulates ISRO on its successful launch of LVM-3.