RYURAKU vs Star Explorer

RYURAKU is an interactive educational simulation app for experiencing fluid dynamics phenomena firsthand. Developer: Fuji Bit Inc. The 6th title in the SUUGAKU / BUTURAKU / DENRAKU / HARAKU / NETURAKU series. The theme is "flow." Discover the wonders of fluid physics through 12 hands-on simulations. 12 simulations in 3 categories: - Flow basics - Streamlines: particles reveal potential flow around a cylinder in a uniform stream. Drag the obstacle and watch the flow field change in real time. - Bernoulli's Principle: flow through a Venturi tube with live pressure gauges. Watch speed rise and pressure drop where the pipe narrows, and see A1v1 = A2v2 at work. - Reynolds Number: laminar-turbulent transition in pipe flow. Adjust speed, viscosity and diameter and see the dramatic change at Re ≈ 2300. - Boundary Layer: a boundary layer growing over a flat plate, from the laminar Blasius solution to turbulent transition at Re_x ≈ 5×10^5. - Darcy's Law: slow flow through porous media such as sand or rock. Adjust permeability, pressure gradient and porosity to experience q = (k/μ)·∇P, the law behind groundwater, oil reservoirs and filters. - Vortices & lift - Vortex: point vortices and their mutual induction. Tap to add a counterclockwise vortex, long-press for clockwise. - Kármán Vortex Street: alternating vortex shedding behind a cylinder, with live Strouhal and Reynolds numbers. - Lift Force: flow around an airfoil and how lift and drag arise. Change the angle of attack or camber and watch the force vectors. - Magnus Effect: asymmetric flow and a sideways force on a spinning cylinder: the physics of curveballs and banana kicks. - Water & gravity - Buoyancy (new): Archimedes' principle. Change the object and fluid densities to find where things float, sink or hang in balance. Drag the object under, let go, and watch it bob until it settles with a submerged fraction of ρ_s/ρ_f. - Torricelli's Law (new): water jetting from a hole in a tank. See the exit speed v = √(2gh), the falling water level and the jet range R = 2√(y₀h). Drag the hole to find the height that throws the water farthest. - Surface Wave: free-surface gravity waves. As the depth-to-wavelength ratio changes, particle orbits shift smoothly from circles (deep water) to flattened ellipses (shallow water). Features: - Real-time parameter adjustment for every simulation - A hint on how to try each screen, plus an explanation with formulas - Live physics formulas and values - Works with large text sizes, landscape, iPad and Split View - Taps and drags can also be done with buttons and sliders (works with VoiceOver and Switch Control) - 16 languages (English, Japanese, Chinese Simplified / Traditional, Korean, Spanish, Portuguese, German, French, Hindi, Indonesian, Russian, Italian, Turkish, Thai, Vietnamese) - Dark mode / Light mode Pricing & ads: - Free. No in-app purchases, subscriptions or paid unlocks - A banner ad (Pangle) is shown at the bottom of the screen - Ads are personalized only if you allow tracking (ATT). You can also turn off personalized ads from "About this app" > "Ad settings" Recommended for: - Students studying fluid dynamics in physics class - Anyone who wants to understand how flow behaves - Teachers looking for interactive teaching materials - Anyone interested in aeronautics or fluid mechanics

APPLE WATCH See the Moon phase, illuminated fraction and moonless observing window, browse astronomy events, and add watch widgets. Sky calculations run on device; weather requires a network connection. Point your iPhone at the night sky and instantly see what you're looking at. Star Explorer names stars, planets, constellations and the Moon in AR, and tells you what's worth seeing tonight from where you are. No sign-up needed to start. The star catalog, sky map and astronomy assistant work offline, so they keep working at dark-sky sites with no signal. WHAT YOU CAN DO - AR star finder: hold up your phone to identify stars, planets and constellations, with comet and meteor-shower layers - Night sky map: a live all-sky chart you can move forward or back in time; search 8,900+ stars, all 88 constellations and all 110 Messier objects - Tonight's sky: Moon phase, visible planets and observing conditions for your location and weather - Sky events: meteor showers, planet oppositions and every solar and lunar eclipse from 2027 to 2030, with reminders - Offline astronomy assistant: ask questions and get an observing plan without a connection - Red-light night mode that protects your night vision - Tonight's Sky widget for your Home Screen - Bite-size astronomy lessons with quizzes, and a stargazing trip planner - Made for iPhone and iPad, including the iPhone Duo inner display Free forever: AR star finder, sky map, sky events, offline assistant, lessons, night mode and widget. Optional purchases: - Pro, all features, lifetime: one-time purchase that unlocks the deep-sky catalog, astrophotography assistant, cloud AI and photo identification - Observing Tools, lifetime: one-time purchase that unlocks the deep-sky catalog and astrophotography assistant - Cloud AI monthly / yearly subscription: unlocks cloud AI answers and photo identification Auto-renewing subscriptions: the subscription period is 1 month or 1 year, and payment is charged to your Apple ID account when you confirm the purchase. The subscription renews automatically at the same price unless auto-renew is turned off at least 24 hours before the end of the current period. Manage or cancel any time in Settings > Apple ID > Subscriptions. The price shown on the App Store purchase confirmation is final. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://star.xinghebit.com/privacy/ Sky data, weather, travel routes and AI answers may contain errors and are not navigation, weather or safety guarantees. Check official sources before observing outdoors. Never look at the Sun through a camera, binoculars or telescope without a certified solar filter.