Flow Disturbance of Flow due to Bends and Obstacles, etc. Time Transients and Spatial Distribution of Fluid Force on Structure Surface FLAVOR-3D: 3-D Fluid Load Analysis Code  Applicable to situations in which structure movement induced by fluid flow does not affect the fluid flow.  The fluid and structural vibration are uncoupled.  Fluctuation of pressure load on components surfaces due to fluid flow is calculated. IMPACT

Inlet Nozzle Downcomer 1.5D 0.3D D Re: 3  10 7 Mesh: 150, kPa Time (s) 0 Power Spectrum Density Frequency (Hz) 10db 4-loop PWR measured value Analysis FLAVOR-3D: 3-D Fluid Load Analysis Code - Application to Pressure Oscillation on PWR Core Barrel -

IMPACT FLAVOR-2D: 2-D Fluid-Structure Interaction Analysis Code  Dynamic structural analysis Fluid force: F(t) Dynamic displacement:  x(t)  Moving boundary  Fluid dynamics analysis x(t) x(t+  t) Flow - Analysis of flow-induced vibration in a single-phase cross flow. - Coupling of fluid flow and dynamic displacement of structure. - Moving boundary in fluid flow analysis by the ALE method.

IMPACT Flow Vertical cylinder was enforcedly oscillated with frequency f Outline of Test  Vortex shedding downstream of the cylinder was measured F vk : vortex shedding frequency  Forced oscillation frequency f and vortex shedding frequency f vk were normalized by Karman vortex frequency f k  Karman vortex under the condition without oscillation was measured F k : Karman vortex frequency FLAVOR-2D: 2-D Fluid-Structure Interaction Analysis Code - Verification (1) -

f : forced oscillation frequency, f k : Karman vortex frequency, f vk : vortex shedding frequency, a : oscillation amplitude, d : diameter of cylinder. (1) Re=490, a/d= f vk / f k f / f k : Test : Analysis 0.5 f vk / f = IMPACT Vortex shedding is not affected by oscillation of the cylinder Vortex shedding coincides with oscillation of the cylinder : “Lock-in” occurs FLAVOR-2D: 2-D Fluid-Structure Interaction Analysis Code - Verification (1) Result of a/d=0.1 -

(2) Re=490, a/d= f vk / f = 1 : Test : Analysis IMPACT f : forced oscillation frequency, f k : Karman vortex frequency, f vk : vortex shedding frequency, a : oscillation amplitude, d : diameter of cylinder. f vk / f k f / f k “Lock-in” phenomena was well reproduced FLAVOR-2D: 2-D Fluid-Structure Interaction Analysis Code - Verification (1) Result of a/d=1.0 -

IMPACT Flow Cylinder with Free End Weight (0.3 lb) Fixed End  The cylinder oscillated due to vortex.  Oscillation amplitude was measured. Outline of Test FLAVOR-2D: 2-D Fluid-Structure Interaction Analysis Code - Validation by Analysis of Free Vibration Test-

IMPACT Amplitude of vibration (mm) Reduced water velocity Analysis Test result* * King, R., et al.: J. Sound and Vibration, 29(2), (1973) FLAVOR-2D: 2-D Fluid-Structure Interaction Analysis Code - Validation Result -

A A' Internal Pump (2.12 m 3 /s, each) 13 m Lower Plenum (552 K) Control Rod Housing In-core Monitor Housing Analysis Region View A-A’ IMPACT Calculated stress on the in-core monitor housing : 9 N/mm 2 (20% lower than the measurement) FLAVOR-2D: 2-D Fluid-Structure Interaction Analysis Code - Application to ABWR 1/6 Sector Test Analysis -