The Science of Ship Design

>> DESIGNING SOMETHING LIKE THE
HULL OF A SHIP CAN BE AN
EXPENSIVE PROCESS.
SO HOW DO YOU RIGOROUSLY TEST
OUT A DESIGN BEFORE YOU EVEN
BUILD IT?
A UNIQUE RESEARCH PROGRAM AT THE
UNIVERSITY OF IOWA MAKES THAT
POSSIBLE, USING SOPHISTICATED
SOFTWARE, MODEL SHIPS, AND AN
ENORMOUS INDOOR POOL.
PROFESSOR FRED STERN LEADS THE
UNIVERSITY OF IOWA'S
SHIP-HYDRODYNAMICS PROGRAM, THE
HOME OF THIS HIGH-TECH FACILITY.
>> THESE ARE CALLED WAVE BASINS.
YOU CAN SEE THE WAVE-MAKERS AT
THE FAR END HERE.
THEY'RE PLUNGER TYPE.
THEY GO UP AND DOWN.
THEY GENERATE EITHER REGULAR OR
IRREGULAR WAVES IN THE BASIN.
THE NEXT PART FOR US, THEN, IS
THE CARRIAGE.
THIS IS A CUSTOM-DESIGNED
CARRIAGE.
IT FOLLOWS THE MODEL.
THERE'S TARGETS ON THE MODEL
THAT THE CAMERAS AND THE
TRACKING SYSTEM USE.
OURS IS UNIQUE INSOFAR AS IT'S
DESIGNED SPECIFICALLY TO CARRY
MEASUREMENT SYSTEMS TO MEASURE
THE LOCAL FLOWS AROUND THE
FREE-RUNNING MODELS.
>> BELIEVE IT OR NOT, THIS
NEARLY $5 MILLION FACILITY WAS
DESIGNED AND BUILT PRIMARILY FOR
THE PURPOSE OF VALIDATING OR
TESTING COMPUTER CODE.
THAT CODE, CFDSHIP-IOWA, IS A
SIMULATION SOFTWARE DEVELOPED AT
THE UNIVERSITY OF IOWA FOR THE
OFFICE OF NAVAL RESEARCH.
IN THE PAST, STERN AND HIS
RESEARCH TEAM VALIDATED THE CODE
BY RUNNING THEIR MODELS IN A
300-FOOT-LONG TOWING TANK, BUT
AS COMPUTER POWER GREW AND THE
CODE BECAME ABLE TO DO MORE
ADVANCED SIMULATIONS, SO IT
REQUIRED A MORE SOPHISTICATED
TOOL FOR VALIDATING.
>> OUR CODES DEVELOPED VERY
RAPIDLY OVER THE LAST, REALLY,
5 TO 10 YEARS, TO THE POINT THAT
WE'RE ABLE TO PREDICT THE EXACT
TRAJECTORY OF THE MODEL,
INCLUDING RUDDERS AND ROTATING
PROPELLERS, AND NO LONGER
RESTRICTED TO CAPTIVE
SIMULATIONS.
THEREFORE, TO VALIDATE IT, WE
NEEDED TO SEE, "WELL, HOW
ACCURATE WOULD THE TRAJECTORIES
BE?"
BY TRAJECTORIES, I MEAN MODELS.
FOR EXAMPLE, YOU START OUT
STRAIGHT AHEAD, YOU GIVE THE
RUDDER A 35-DEGREE ANGLE, AND
IT'S GONNA GO IN A CIRCLE.
WE WANT TO KNOW, WHAT'S THE
RADIUS OF THAT CIRCLE?
ANOTHER TYPE IS A ZIGZAG TEST
WHERE YOU PUT THE RUDDER 10, 10,
20, 20, AND THEN YOU PREDICT
WHAT'S KNOWN AS THE OVERSHOOT.
THERE'S HALF A DOZEN OR SO OF
THESE TRADITIONAL TESTS, BOTH IN
CALM WATER AND WAVES, THAT SHIPS
HAVE TO BE ABLE TO DEMONSTRATE
THE CAPABILITY OF PERFORMING TO
A SATISFACTORY STANDARD IN ORDER
TO BE BUILT.
AND SO OUR FOCUS IS NOT ACTUALLY
DESIGN.
OUR FOCUS IS DEVELOPMENT OF THE
TOOLS.
>> WHILE THE WAVE BASIN WILL
ENABLE NEW ADVANCES IN
HYDRODYNAMICS, PROFESSOR STERN
SAYS IT INDICATES THE DIRECTION
MUCH OF SCIENCE IS ALREADY
HEADING.
>> YOU KNOW, THE FUTURE OF
ENGINEERING IS SIMULATION-BASED
DESIGN, AND, IN FACT, WE CAN
SIMULATE THINGS WE CAN'T
MEASURE.
SO YOU BEGIN TO SEE A MAJOR
SHIFT IN THE SCIENTIFIC METHOD,
WHERE WE WENT FROM ARISTOTLE,
OKAY, WHO BASED EVERYTHING ON
LOGIC -- HE DIDN'T BOTHER TO --
YOU KNOW, HE THOUGHT MEN AND
WOMAN HAD A DIFFERENT NUMBER OF
TEETH IN THEIR MOUTHS.
IT'S ONE OF MY FAVORITE STORIES.
OF COURSE, THEY DON'T, AND HE
COULD HAVE FIGURED THAT OUT
EASILY BY JUST LOOKING IN HIS
WIFE'S MOUTH, BUT -- THEY'RE
TEETH.
BUT, NO.
SOME LOGIC AND NO VALIDATION.
GALILEO SAID, "OKAY, VALIDATION.
EXPERIMENTS.
PHYSICAL OBSERVATIONS."
BUT THERE'S LIMITS THERE, TOO.
NOW WE COME BACK TO, IF YOU
THINK OF SIMULATION TECHNOLOGY
AS REALLY LOGIC, SO NOW WE'RE
COMING BACK TO LOGIC -- LOGIC,
THOUGH, COUPLED WITH THE
EXPERIMENTS.
THIS IS THE ENGINE OF
SIMULATION-BASED DESIGN, AND, IN
THAT SENSE, EACH OF THESE STEPS
ARE JUST LITTLE, YOU KNOW, STEPS
ALONG THE WAY.
WE'LL ALWAYS NEED THE SMALLER
FACILITIES, THE MEDIUM-SIZE,
AND THE LARGER FACILITIES.
THIS FACILITY IS HALF THE SIZE
IT SHOULD BE FOR ACTUAL
INDUSTRIAL USE, BUT FOR BASIC
SCIENCE, IT'S JUST PERFECT.
>> TO LEARN MORE ABOUT SHIP
HYDRODYNAMICS AND THE SCIENCE OF
ALL THINGS FLUID, VISIT...