Відео

As a (maybe too) comprised answer: Darcy's law can be written in different ways (dependent on the hydrological 'problem' at hand). Yes, q in one direction (a specific discharge or volume flux density in m/day) =-K i . Q (a discharge or volume flux in m3/day) = -K i A, with A (in m2) being the total ground area perpendicular to the water flow. If you use Darcy's law in a vertical cross section for confined groundwater, the latter reduces to Q' (m2/day) = -K D i, with D being the saturated thickness or depth (in m) of the confined aquifer; if you use Darcy's law in a vertical cross section for unconfined groundwater, the latter reduces to Q' (m2/day) = -K h i, with h being the hydraulic head (in m) in the unconfined aquifer. Probably better is: If you want to come to full grips with groundwater flow in an unconfined aquifer (Dupuit-Forchheimer), I would recommend you to start off by (again?) studing the contents of lecture 3, part 1 of the playlist 'Physical Hydrology' on my UA-cam channel. After this, proceed by studying lecture 3, part 2; lecture 4; lecture 5; and lecture 6. This sequence builds up to the 'problem' of groundwater flow in an unconfined aquifer (in lecture 6; or in this stand-alone version). If you have any further questions (on the way), just let me know. I hope this is helpful or at least gets you started. Best wishes, Martin

Hydrology + Dutch treat 😀

Thanks! My pleasure!

Thank you! You're most welcome!

Thank you; my pleasure! Should you have any future questions on the material explained in my videos, please feel free to contact me.

Dank; goed om te horen! Hydrologie is (te?) rijk aan termen: filtersnelheid (of Darcy snelheid) is (dus) hetzelfde als de volumestroomdichtheid (specifiek debiet). Ik gebruik de aanduiding filtersnelheid liever niet om verwarring met de effectieve (grondwater)snelheid te voorkomen.

@@PhysicalHydrology ik heb uw boek besteld hoor! Ben erg benieuwd. Weer eens een andere invalshoek dan ‘Nortier’ is voor mij weer leerzaam.

Thanks; you're welcome!

Hi Max, thanks; good to hear! Should you have any questions with regards to the contents, just let me know. Best of success, Martin

Groundwater does not need a local heat source to flow upwards.

Thanks. Will do.

Thank you, you're welcome! Best of success! Cheers, Martin

Thank you, Carlos; good to hear!

Thank you, you're welcome! Best of success! Cheers, Martin

@@PhysicalHydrology Sir may u have more success in life. You r one of the best teacher around the globe

Good to hear; you're welcome!

Thanks; you're welcome!

Any shape will do: no problem! In practice, however, they are usually circular/cylindrical or square.

Thank you! You're welcome! Best of success with your PhD research! Best regards, Martin

Thanks. You can turn on the subtitles if you wish; you may find this helpful, I am not sure.

You're welcome. Good luck with your preparation and the Science Olympiad.

Correct: log(e)=0.4343. Explanation: It has to do with converting from natural logarithms (notation: ln; logarithms to the base of the mathematical constant e) to common logarithms (notation: log; logarithms with base 10). The conversion can be figured out as follows: log(10)=1; ln(10)=2.302585; thus: ln(10)=2.302585*log(10). Actually, this goes for all numbers larger than or equal to 0 (zero). Thus: ln(x)=2.302585*log(x) with x>=0, which we can rewrite as: log(x)=(1/2.302585)*ln(x) or log(x)=0.4343*ln(x). So, there your factor 0.4343 pops up! From my formula it follows that alpha=(lnQ0-lnQt)/(tt-t0); if you replace ln with log, you will get: alpha=[2.302585*(logQ0-logQt)]/(tt-t0) or alpha=(logQ0-logQt)]/[0.4343*(tt-t0)], the formula you found in literature.

@@PhysicalHydrology Sorry for bothering you. After a while I figured out why. I was considering log(e) = 1, because most of the time, I write ln as log. The correct derivation of the formula is: Qt = Qo*e^(-at) log10(Qt) = log10(Qo*e^(-at)) log10(Qt) = log10(Qo)+log10(e)^(-at) log10(Qt) = log10(Qo)-at(log10(e)) --> here's my mistake; a = log10(Qo) - log10(Qt) / log10(e)*(t - to)

@@matheuspena8 No bother at all! Good that it's all clear!

My pleasure! Concerning your comment: Q with a prime equals Q divided by W (is correct): your scaling down (one 'step') from m3/day to m2/day; little q (= volume flux density = specific discharge) equals Q divided by A (A =D*W): then, you are scaling down (two 'steps') from m3/day to m/day. The advantage of using Q with a prime is that you only have to deal with variables of the cross-section.

​@@PhysicalHydrology Thank you very much for your quick respond and my appologies, I didn't see Prime sigh next to the Q. As I expected, you're absolutely right. My honor to take your courses here. Thank you so much for sharing your science with anyone who is looking...

@@i.hemati No problem. In case you have any further questions, do not hesitate to contact me, best at my university e-mail address.

Thanks! Maybe you like my explanation of 'Drive my car' by the MonaLisa Twins too? Just made this, to try out the workings of VideoPad, and for the fun of it! :-) Cheers, Martin

Hello Awale, Thank you. You're welcome. If you have questions concerning the video lectures, please do not hesitate to contact me! Best regards, Martin

You're welcome! Should you have questions concerning the contents, please do not hesitate to email me. All best wishes, Martin Hendriks

@@PhysicalHydrology Thanks again. I don't have any questions about the content but we need more contents like these, especially Hydraulic design, hydropower and groundwater ❤️

Hello Hamed alkabi, Introduction to Physical Hydrology by Martin R. Hendriks (Oxford University Press); for info on the book, see: global.oup.com/academic/product/introduction-to-physical-hydrology-9780199296842?cc=nl&lang=en& Book is also available as Kindle edition (with free app to read on your smartphone, tablet or computer). Best wishes, Martin

Martin R. Hendriks thank you very much professor

Hi Daniel, this may be helpful: INTO TEMPTATION - Neil Finn (Crowded House; Paul Kelly and Neil Finn) Em - D/F# - C - B7! ! You opened up your door I couldn't believe my luck You in your new blue dress Taking away my breath The cradle is soft and warm Couldn't do me no harm You're showing me how to give (change after D/F#) G - D - Em - G - D - B7 Into temptation Knowing full well The earth will rebel Into temptation A muddle of nervous words Em - D/F# - C* - A5*- B5*! - B7* *! Could never amount to betrayal Em - D/F# - C - B7! The sentence is all my own The price is to watch it fail And as I turn to go You look at me for half a second With an open invitation For me to go (change after B7) G - D - Em - G - D - B7 - C - D Into temptation Knowing full well the Earth will rebel Into temptation Safe in the wide open Arms of hell G maj - A - C - Bm - G maj - A We can go sailing in Climb down Lose yourself when you linger long Into temptation Right where you belong (Harmonica) The guilty can never sleep *! In the long slow hours of morning Experience is cheap Well, I should’ve listened to the warning (change after B7) The cradle is soft and warm Ah Into temptation Knowing full well the Earth will rebel Into your wide open arms No way To break the spell Break the spell Don't tell   INTO TEMPTATION - Crowded House (Neil Finn) The chords are played bass note first. Intro and Verse Em 0220xx D/F# 2002xx C 3320xx B7 x212xx Chorus G 320003 D x00232 Em 022000 022030 022020 022030 G 320003 D x00232 B7 x212xx Start of new verse Em 0220xx D/F# 2002xx C 0320xx A5 x022xx B5 x202xx B7 x212xx End of 2nd chorus C 332010 D x00232 Intermezzo G maj x2000x A 002220 C 332010 Bm xx4432 G maj x2000x A 002220 Outro C 032010 D x00232

Martin R. Hendriks Omy! Yes, yes, YES! Tyvm!!