  Next-generation radio arrays, including the Square Kilometre Array (SKA) and
its pathfinders, will open up new avenues for exciting transient science at
radio wavelengths. Their innovative designs, comprising a large number of small
elements, pose several challenges in digital processing and optimal observing
strategies. The Giant Metrewave Radio Telescope (GMRT) presents an excellent
test-bed for developing and validating suitable observing modes and strategies
for transient experiments with future arrays. Here we describe the first phase
of the ongoing development of a transient detection system for GMRT that is
planned to eventually function in a commensal mode with other observing
programs. It capitalizes on the GMRT's interferometric and sub-array
capabilities, and the versatility of a new software backend. We outline
considerations in the plan and design of transient exploration programs with
interferometric arrays, and describe a pilot survey that was undertaken to aid
in the development of algorithms and associated analysis software. This survey
was conducted at 325 and 610 MHz, and covered 360 deg$^2$ of the sky with short
dwell times. It provides large volumes of real data that can be used to test
the efficacies of various algorithms and observing strategies applicable for
transient detection. We present examples that illustrate the methodologies of
detecting short-duration transients, including the use of sub-arrays for higher
resilience to spurious events of terrestrial origin, localization of candidate
events via imaging and the use of a phased array for improved signal detection
and confirmation. In addition to demonstrating applications of interferometric
arrays for fast transient exploration, our efforts mark important steps in the
roadmap toward SKA-era science.
