Matsayin Hudson

Matsayin Hudson
formula (en)

Matsayin Hudson, wanda aka fi sani da Tsarin Hudson, daidaitattun ne da Injiniyoyin bakin teku ke amfani da su don lissafin mafi ƙarancin girman riprap (armourstone) da ake buƙata don samar da halaye mai gamsarwa ga tsarin rushewa kamar masu fashewa a ƙarƙashin hari daga yanayin guguwa.

Injiniyoyin Sojojin Amurka, Waterways Experiment Station (WES) ne suka kirkiro daidaitattun, biyo bayan bincike mai zurfi na Hudson (1953, 1959, 1961a, 1961b)

Daidaitawa ta farko

Daidaitawar kanta ita ce:

$W={\frac {W_{r}H^{3}}{K_{D}(S_{r}-1)^{3}\cot \theta }}$

inda:

• W shine nauyin ƙirar makamai na riprap (Newton)
• γ r {\displaystyle \gamma _{r}} shine takamaiman nauyi ginshiƙan makamai (N / m³)
• H shine tsawo na raƙuman ruwa a ƙafar tsarin (m)
• 'D="mwLQ">K wani nau'i ne na kwanciyar hankali mara ma'ana, wanda aka cire daga gwaje-gwaje na dakin gwaje-gaje don nau'ikan ginshiƙan makamai daban-daban da kuma ƙananan lalacewa (wasu ginshiƙai da aka cire daga Layer na makamai) (-):

• 'D="mwNA">K = kusan 3 don dutse na halitta
• 'D="mwOA">K = kusan 10 don tubalan siminti na wucin gadi

• Sr = (ρr / ρw shine dangi na dutse, watau (ρr/ ρw - 1) = kusa da 1.58 don dutse a cikin ruwan teku
• 'wr">ρ' da ρw sune yawan dutse da (teku) ruwa (-)
• θ shine kusurwar murfin tare da kwance

Sabuntawa da aka yi

An sake rubuta wannan daidaitattun kamar haka a cikin shekarun da suka gabata:

${\frac {H_{s}}{\Delta D_{n50}}}={\frac {(K_{D}\cot \theta )^{1/3}}{1.27}}$

inda:

• H _s zane mai mahimmanci tsawo a yatsan tsarin (m)
• Δ shine dangi mara girma na dutse, watau (ρr / ρw - 1) = kusa da 1.58 don dutse a cikin ruwan teku
• 'w">ρ da ρ sune yawan dutse da (teku) _r (kg / m³)
• D shine matsakaicin diamita na ginshiƙan makamai = (W₅₀/ρ_r) ^1/3 (m)
• 'D="mwcw">K wani nau'i ne na kwanciyar hankali mara ma'ana, wanda aka cire daga gwaje-gwaje na dakin gwaje-gaje don nau'ikan ginshiƙan makamai daban-daban da kuma ƙananan lalacewa (an cire wasu ginshiƙai daga Layer na makamai) (-):

• 'D="mweg">K = kusan 3 don dutse na halitta
• 'D="mwfg">K = kusan 10 don tubalan siminti na wucin gadi

• θ shine kusurwar murfin tare da kwance

Ana iya ɗaukar dutsen makamai mai ɗorewa idan lambar kwanciyar hankali N<_s id="mwhw">s = H_s / Δ D_n50 < 1.5 zuwa 2, tare da lalacewa da sauri don Ns > 3. Wannan tsari ya kasance shekaru da yawa ma'auni na Amurka don ƙirar dutse a ƙarƙashin tasirin aikin raƙuman ruwa A bayyane yake, ana iya amfani da waɗannan daidaitattun don ƙirar farko, amma gwajin samfurin sikelin (2D a cikin raƙuman raƙuman, da 3D a cikin kwandon ruwa) ana buƙatar gaba ɗaya kafin a fara gini.

Rashin daidaituwa na tsarin Hudson shine cewa yana da inganci ne kawai ga raƙuman ruwa masu tsayi (don haka ga raƙuma a lokacin guguwa, kuma ƙasa da raƙuman raƙuman). Har ila yau, ba shi da inganci ga masu hana ruwa da kariya ta bakin teku tare da tsakiya mai hana ruwa. Ba zai yiwu a kiyasta matakin lalacewa a kan ruwa mai hana ruwa a lokacin guguwa tare da wannan tsari ba. Saboda haka a zamanin yau ana amfani da Tsarin Van der Meer ko bambancinsa don armourstone. Don abubuwan da ke cikin ruwa sau da yawa ana amfani da bambancin tsarin Hudson.