Critical valve-closure time
API · /waterhammer-api
Water Hammer API
healthy
3,906 Subscribers
Water-hammer (hydraulic-transient) maths as an API, computed locally and deterministically — the surge-pressure, wave-speed and valve-timing numbers a piping or plumbing engineer guards a system with. The surge endpoint applies the Joukowsky equation Δp = ρ · a · Δv: a sudden stop of the flow spikes the pressure by the fluid density × the pressure-wave speed × the velocity change — stopping 2 m/s of water at a ≈ 1200 m/s adds about 24 bar (348 psi), far above the line pressure, which is what bangs the pipes and can split fittings. The wave-speed endpoint gives that pressure-wave speed: a = √(K/ρ) in a rigid pipe (≈ 1,480 m/s for water), slowed in a real elastic pipe to √(K/ρ) ÷ √(1 + (K·D)/(E·t)) — a thin or plastic pipe gives a lower wave speed and a gentler surge, which is why PVC tolerates hammer better than steel. The critical-time endpoint gives 2L/a, the round-trip time of the wave: close a valve faster than this and you get the full Joukowsky surge, slower and the returning relief wave eats into it, so sizing closure times (or fitting a surge tank or air chamber) above the critical time is the standard cure. Everything is computed locally and deterministically, so it is instant and private. Ideal for piping- and plumbing-design tools, pump-station and pipeline-surge analysis, and hydraulic-engineering utilities. Pure local computation — no key, no third-party service, instant. Idealised single-pipe transient. 3 compute endpoints. For steady pipe pressure drop use a Darcy API; for pump head and affinity a pump API.
api.oanor.com/waterhammer-api
API health
healthy- Uptime
- 100.00%
- Server probes · 24h
- Avg latency
- 82 ms
- Server probes · 24h
- Subscribers
- 3,906
- active
- Total calls
- 0
- last 7 days
Pricing
Pick a tier — billed monthly, cancel anytime.
Free
Free
- 4,900 calls / month
- 2 requests / second
- Hard cap (429 above quota, no overage)
- 4,900 calls/month
- 2 req/sec
- Surge + wave speed + critical time
- No credit card
Starter
€12.60 /month
- 50,500 calls / month
- 6 requests / second
- Hard cap (429 above quota, no overage)
- 50,500 calls/month
- 6 req/sec
- Elastic-pipe wave speed
- Email support
Pro
€39.00 /month
- 216,000 calls / month
- 15 requests / second
- Hard cap (429 above quota, no overage)
- 216,000 calls/month
- 15 req/sec
- Pipeline & pump-station surge pipelines
- Priority support
Mega
€120.50 /month
- 1,125,000 calls / month
- 40 requests / second
- Hard cap (429 above quota, no overage)
- 1,125,000 calls/month
- 40 req/sec
- Firm & utility scale
- Dedicated SLA
Built by
Related APIs
Other APIs with overlapping tags.
Hydraulic Cylinder API
Hydraulic-cylinder engineering maths as an API, computed locally and deterministically — the force, speed and oil-volume numbers a fluid-power designer, machine builder or hydraulics technician sizes a cylinder with. The force endpoint gives the push and pull from the bore, rod diameter and working pressure: extending, the oil acts on the full bore area, so the cylinder is strongest pushing out; retracting, it acts only on the annulus left by the rod, giving less force — a 100 mm bore with a 56 mm rod at 160 bar pushes about 125.7 kN out but pulls only 86.3 kN back, which is why a press or an excavator does its hard work on the extend stroke. The speed endpoint gives the piston speed from the pump flow (speed = flow ÷ area), so extending is the slower stroke and retracting the faster, the trade-off every circuit designer balances against force. The volume endpoint gives the swept oil volume per stroke for extend and retract, the rod displacement and the bore-to-annulus area ratio — the differential (regeneration) ratio used to speed the extend stroke in a regen circuit — so the pump, tank and lines can be sized for the larger volume. Everything is computed locally and deterministically, so it is instant and private. Ideal for fluid-power and machine-design tools, hydraulics-sizing calculators, mobile- and industrial-equipment utilities, and engineering apps. Pure local computation — no key, no third-party service, instant. Ideal-area estimates — allow for friction, back-pressure and efficiency. 3 compute endpoints. For Pascal force-multiplication use a hydraulics API; for valve sizing a valve-flow (Cv/Kv) API.
api.oanor.com/hydrauliccylinder-api
O-Ring Seal API
O-ring seal-design maths as an API, computed locally and deterministically — the squeeze, gland and stretch numbers an engineer or maker designs a seal to. The squeeze endpoint gives the compression that makes the seal: squeeze = (cross-section − gland depth) ÷ cross-section, so a 0.139-inch cord in a 0.113-inch deep groove is squeezed 18.7 %, and it grades the result — roughly 10–16 % suits dynamic (reciprocating) seals and 15–30 % static ones — and, given the groove width, the gland fill percentage, which should stay under about 85 % so the rubber has room to expand from heat or fluid swell. The gland endpoint works the other way: from the cross-section and whether the seal is static or dynamic (or a target squeeze) it returns the groove depth and a width sized for about 70 % fill — typically 1.3 to 1.5 times the cross-section — plus a corner radius. The stretch endpoint checks installation: stretch = (mating diameter − o-ring ID) ÷ ID, which should stay under about 5 % on a rod because stretching thins the cross-section and steals squeeze. Everything is computed locally and deterministically, so it is instant and private. Ideal for mechanical-engineering, hydraulics, pneumatics, vacuum and product-design app developers, seal-selection and gland-design tools, and CAD plugins. Pure local computation — no key, no third-party service, instant. Inches or millimetres. Live, nothing stored. 3 compute endpoints.
api.oanor.com/oring-api
Torricelli Efflux API
Torricelli efflux and orifice-discharge maths as an API, computed locally and deterministically. The velocity endpoint applies Torricelli's law, v = √(2·g·h) — the speed at which fluid jets from an orifice under a head h equals that of a body that has fallen the same height — and returns the ideal and the actual jet velocity (corrected by a coefficient of velocity), and, if you give the orifice diameter or area, the ideal and actual volumetric discharge Q = Cd·A·√(2gh) in litres per second and minute, cubic metres per hour and US gallons per minute. The drain-time endpoint computes how long a vertical cylindrical tank takes to empty through an orifice, t = (2·A_tank)/(Cd·A_orifice·√(2g))·(√h0 − √h1), from the tank and orifice sizes, the starting head and an optional final head, with the initial flow rate. The range endpoint gives the horizontal distance a jet from a side orifice travels before it lands, x = 2·Cv·√(h·y), from the head above the orifice and the orifice's height above the ground, with the jet velocity and time of flight. The discharge and velocity coefficients default to 0.62 and 0.97 and can be overridden, as can gravity. Everything is computed locally and deterministically, so it is instant and private. Ideal for fluid-mechanics and hydraulics tools, tank-drainage, irrigation and process-engineering apps, and physics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is orifice efflux and tank drainage; for pipe continuity Q = A·v use a flow-rate API and for tank volume and fill level use a tank API.
api.oanor.com/torricelli-api
Open Channel Flow API
Open-channel flow maths as an API, computed locally and deterministically with the Manning equation. The flow endpoint computes the discharge and velocity of water in an open channel — rectangular, trapezoidal, triangular or circular (a part-full pipe) — from the flow depth, the channel dimensions, the channel slope and the Manning roughness coefficient n: it works out the flow area, the wetted perimeter and the hydraulic radius, then applies Q = (1/n)·A·R^(2/3)·S^(1/2) and V = Q/A, reporting the discharge in cubic metres per second and hour, litres per second, cubic feet per second and US gallons per minute. The normal-depth endpoint reverses it: given a target discharge it solves for the normal depth by bisection and returns the resulting area, velocity and a discharge check. The roughness endpoint is a reference of typical Manning n values, from smooth PVC (0.009) and concrete (0.013) through earth and gravel to rocky natural streams (0.05); pass a material name or an explicit n. Dimensions are metric (metres by default, or cm, mm, ft, in). Everything is computed locally and deterministically, so it is instant and private. Ideal for civil and drainage engineering tools, stormwater and culvert design, irrigation and hydrology apps, and environmental modelling. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is open-channel (Manning) hydraulics; for full-pipe flow rate from diameter and velocity use a pipe-flow API.
api.oanor.com/manning-api
Frequently asked questions
Quick answers about pricing, quotas, and integration.
How do I get an API key for Water Hammer API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Water Hammer API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Water Hammer API?
Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.
How much does Water Hammer API cost?
Water Hammer API has a free tier with 100 calls / month. Paid plans start at €12.60 / month with higher quotas and faster rate limits.
Can I cancel my subscription anytime?
Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.
Is Water Hammer API GDPR-compliant?
All requests to Water Hammer API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.
Pick an endpoint from the list on the left to see its details and try it.
Code snippets
Sign up to get an API key, then call any path under your slug.
curl https://api.oanor.com/waterhammer-api/SOME_PATH \
-H "x-oanor-key: oanor_test_..."const res = await fetch("https://api.oanor.com/waterhammer-api/SOME_PATH", {
headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();$ch = curl_init("https://api.oanor.com/waterhammer-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);import requests
r = requests.get(
"https://api.oanor.com/waterhammer-api/SOME_PATH",
headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())Ratings
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